Is it ok to play 2person coop in bdl2?

I'd say it'd still be a good experience with 2 people.
hell, i've only been playing it solo.

And if one player has all DLC and other player has only base game - how they will play co-op?

it can be fun with 2 people,the more people the harder it gets and the better loot that drops

the best thing to do is see if you have friends that play it,the other thing you can do is play solo but allow people to play the game with you,that is how i found players,be warned though some people like to cheat but easy enough to avoid them

it really depends on what your playing for as some take it serious and hate losing others just want to have fun and do not care how it is played

at this moment i am burned out on borderlands so i have not touched it much in awhile

and also keep in mind until you find decent players you will run across idiots and loot ninja,but they can be kicked by the host

some people take the game serious,some play for fun

usually when i join a game i ask what people are doing and i observe there playing if notice any cheating i leave

usually when i host when people join i tell them they can join as long as they want to have fun,are not cheating,and do not ninja stuff,i also make it clear that the host gets first pick of drops,and when i join i do the same

it does not always work out like that because of the chance of loot ninas or other things if strangers join but really over all most players are decent

Ok thanks for the advice bros. Decided to buy it :D

I played borderlands 1 and 2 with my girlfriend, both are perfectly well suited for 2p coop.

Why the hell wouldn't it be? There's actually better communication with only 2 people than with 4, in my opinion. But the game's pretty friggin' awesome even solo.

Considering that I just finished on normal, solo, I would guess more the merrier.
Be sure that your friend will play because if you gonna play this solo, there no reason for more then one play through. Gun play is ok, story is a joke, so if I wasn't aiming for 100% quest done I would finished playing it long ago.
I'll try to find some people to play with in True Vault Hunter mode, if not, uninstall is easy.

it seems to me you're going about this the wrong way.

1) Buy the DLC's. They're worth getting, especially when on sale.
2) Make sure your friend has all the DLC's, too.
3) Find a BL2 group. There are plenty of people who still play the game. (My group has been distracted with other games, recently.)