Ok, I have played and beat Dark Souls 2, almost twice (just have to kill Gaint Lord and then Nashadra again). I find the game disappointing in many ways.
Environment -
While Demon Souls used a multitude of different sub worlds, the worlds remained consistent and interconnected with itself throughout the game.
Dark Souls made one, amazingly well put together, giant interconnected world. Moving through areas felt like wandering the kingdom and forest itself.
Dark Souls 2 feels completely inorganic, I still can't get over Earthen Peak's connection to Iron Keep (you ride a straight elevator up from the top of a giant windmill into a area surrounded by lava and volcanoes. The windmill was one of the tallest structures in the area, doesn't make any sense.) The hidden walls are completely inconsistent and requires guides to inform the player, instead of using the environment as Dark Souls would have used.
All the areas just felt like samples of something that could have been expanded on so much more. I hated getting in elevators because it always meant that I would be loaded into a completely different kind of area.
Then the game layout gives no direction what-so-ever, not a "creator wants you to go here" but a "here's a path you can follow". With so many places requiring random requirements, forcing multiple loop backs from later areas, or making the player almost completely blind, it unnecessarily hard to find paths without guides showing you and reminding you of what you missed.
Enemies -
Demon Souls was rough when it came to enemy placement and combat, but observation and strategy made up what it denied in player "play style" variety.
Dark Souls was incredibly well done, the possibilities and limitations of enemies were incredibly well executed, with exceptions. Through trial and error, players could develop a huge variety of play styles. One I loved was using sound from arrows to lure enemies around. You could, almost always, step into a location and observe the surroundings, what you can use to your advantage, and formulate multiple means of approach that could manipulate the limitations of the enemies.
Dark Souls 2 It felt like it was taking steps towards Demon Souls, riddled with the constant ambushes and crazy high poise. Unlike with Dark Souls, enemies capabilities were not something you could access through observation, I often found myself dead because the enemy looked and acted significantly slower than one or 2 of their, less often used, attacks. When entering a new area, if I couldn't see my enemy, it was due to them hiding for an ambush. For the enemies that could be seen, they were clumped together in a group with their aggro, almost always, tied together. Often times, the best way to play the game was with a wide hitting and high poise damaging weapon's (great and ultra weapons), or simply with high damaging long distance spells.
Then there's the ridiculous turn radius that allows enemies to turn while in the middle or recovering from their animation unless you trigger a roll at the right time. (At one point I was screaming at a knight in Iron Keep, who was picking up his sword after trowing it down, but was gliding to meet my face as I tried to run around him for a back stab...) It's ridiculous.
Then there's the inconsistent damage, and limitations of spawn rates, that I could go into a huge argument about. A (had been then) melee only friend of mine struggled in the "Shrine of Amana" against the incredibly long range and high hitting priestesses spamming magic homing missile.
Armor, Weapons, Spells -
It's been three games, and yet you still can't do anythign new with armor except simply level it to it's consistent max. Where You either equip for defense or style, and their is always a consistent "best" set(s). Since invasions are random, I have to go offline if I want to dress for stylistic preference.
A lot of weapons are counterproductive PvE wise. I love how much easier it is to make powerful weapons, but due to that, theirs a strong consistency of "best weapon". Often times, the only difference in a weapon is its appearance and attack animation to which their are very few different animations, so it often simply comes down to numbers in damage. Scaling rates made in infusion are random, I can't remember Dark Souls crafting atm to compare though.
For NG+, I used Strong Lightning Bolt to kill everything for 1-2 hit kills, and with a little more than 80% of the bosses having weaknesses to lightning, I've been coasting along really nicely, which is kinda boring. Spell really doesn't need a strategy, I never went with a magic build before to compare, but with AoE's and DoT's (Dark Fog), I barely have to get my hands dirty with melee and rolling on the ground.
My play strategy, in Dark Souls and Demon Souls, was almost always one-handed swords and daggers combined with bows, but with limitations on spawns (in DK2), meant limitations on arrows, that and the removal of head shots forced me to give up on the bow, and the high poise rate forced me out of using daggers and one-swords, so I went with greatswords and shield for poise damage and spells for range, but ended up completely relying on spells.
Bosses... There was a very clean and consistent pattern of, making a "wide open area" and "placing a boss in there", the only variety was that there were occasionally a mob of common enemies in their as well.
Some of my favorite battles throughout the games were Demon Souls "Tower Knight" and his army of archers lining the walls, the blind "Old Hero", "Storm King" and his army of manta's vs the "Storm Ruler's Sword", narrow passageway towards the "Armor Spider". In Dark Souls their was running up the ladder to jump down on "Tarus Demon" to then slip past to the other side, slipping past him again to run back up the ladder, there was the constantly changing battlefield of "Quelaag's" boss area due to her lava attacks, and running up the stairs to fight the dogs one-on-one in "Carpa Demon's" boss area.
The few boss fights I found interesting, the ones that used environment, in Dark Souls 2 was "Flexile Sentry" and the beam in the center of the map which could be manipulated as a shield, "The Chariot" and his area was actually kinda fun (the journey too, if you died, was a bitch though), "The Rotten's" flaming pits which really were not as hard to deal with as Quelaag's.
The bosses I had a hard time with was only ever due to their high damage or being mobbed, exception being "The Demon of Song" I didn't have to formulate strategies with any of them in the way I had to do say with... "Moonlight Butterfly". Then there were bosses that felt very much like cutouts from Dark Souls, "Old Dragon Slayer", "Belfry Gargoyles", and "Royal Rat Authority", I really don't know what to think about these...
Story wise... The point and perspective chosen was boring and random as far as I could understand, greatly lacking the environmental details Dark Souls had, the environment being mostly meaningless to the story by comparison.
The player is a random hollow killing everything to stay sane and told, by other npc's (firekeeper's), to take the "true" throne and the kingdom from King Vendrick, for no apparent reason or purpose.
There's a huge back story of a kingdom of ruin, given prosperity through Vendrick's actions and his mysterious queen, but lost to the curse, even the bits of war with giants. But instead of exploring the build up or destruction of all the chaos, your thrown in after all the dust settles... Everything is over, there's no one to fight for, nothing but explorers and outcast remain their.
Most disappointing, the ending really doesn't explain anything, especially the curse or the "dark". I can guess it has something to do with the original fire, but that's it.
All I got is a bunch of questions... Like, how was Benhart able to enter the memories without the kings ring, only article of importance on him is his bluemoon sword which is...
An inconsistency in the world is that you can kill the npc's for good... Despite some of them being hollow and with hollows being unable to die... I kinda have a problem with this.
I tried really hard not to let my perception of Dark Souls and Demon Souls effect my view of Dark Souls 2, but I rarely had fun exploring the world as I had with the previous 2 titles. I really tried to love Dark Souls 2, but it felt like a hollow cash grab through continuation (sequels) that failed to capture what Dark Souls accomplished so well... I expected Dark Souls 2 to cover some of the open bits from the first, but it doesn't seem too.
This whole post is mostly me venting, I expected "a lot", and was disappointed to the point I couldn't let go of all the things that bothered me.