they are both great but you cant really compare the two very well. DA:O is a pure tactical RPG while DA2 is more of a hack-and-slash meets RPG with dumbed down RPG elements. both games are great at what they do but if you compare DA2 to DA:O or the other way around you will undoubtedly have some gripes
DA:O does tactical RPG the way it was meant to be done: it is very in depth, it has a huge universe to play in, it has a large tech tree for each class, its very tactically minded, and it requires a good mix of classes to be effective
DA2 is a great RPG for the action junky who traditionally enjoys adrenaline packed games like most modern shooters: it has fast pace action, it limits the gear sorting so you can spend less time in the inventory and more time in the action, it has RPG elements without drowning the player in them, it is tactical for those who are into that but it has an autopilot mode for those who dont, and it is short and to the point
what i find the majority of DA2 haters dislike about DA2 is that it is not like DA:O. while i do agree (and side with them for the most part) i also understand why the switch was made. the creators wanted to cast a wider net in order to catch more of the gamer market and get higher sales. i also hear alot of gamers hating the switch because DA:O did tactical RPG perfect and to see such a great franchise switch gears completely from a series that has so few titles to begin with is a tragic loss
if i had my way i would have kept DA2 the same style as DA:O but to be fair the switch to this hack-and-slash RPG is both more viable for the current gaming market and these type of games are much more simple/ time consuming to make and so you can pump out sequels much faster. this is simply a money grab