Personally, it feels like Crytek UK focused too much on the details in Crysis 2. You got all kinds of cool things and details in just about everything. Some weapons pierced armour or ignored it, you got modules based on your playstyle, medal unlocks from just about everything, activating armour mode takes time and so on. Those were all nice ideas, some are something I even miss when I play Crysis 3 (especially the way you unlocked modules).

On the other hand, the core gameplay felt like something what the developers thought about after they had coded all the cool ideas. Compared to the rest of the games in the series, the gameplay is much slower, the firefights don't feel exciting, grenades (and melee) are extremely effective and so on. Not to mention the annoying glitches, which forced you to reboot in order to get a weapon you wanted, upgrade modules once again and so on.

Crysis 3 does have a lot of annoying problems, which can test patience. The most annoying thing probably being the framerate issues you receive when you host a match with x amount of players (5-15 FPS in Coastline, take that PC players!). But unlike Crysis 2, the core gameplay is fun. There are balance issues and weird hit detection stuff but the game offers more funny stuff.

Bored of shooting stuff? Run around with a pole! Tired of serious matches? Play Hunter or Frenzy! Still not fun? Cause weird physics glitches with R.E.X! The game also feels much more fast paced, and the map design makes it a lot more fun to go fast.

Both games are buggy and (sometimes) laggy messes, but Crysis 3 is a funny mess in my opinion.