i think you are misinformed. first your off with there were more glitches in bo2 than in bo1. the maps have been rushed since the bo2 dropped, creating massive amounts of glitches and bugs. bo1 didnt have buildables. bo2 is riddled with them creating even more glitches.
second, only the jet gun and paralyzer have infinite ammo as far as the bo2 WW go. the sliquifier and blundergat use ammo like other guns. also i am unaware of the unbreakable trap glitch. have not seen that one yet.
what makes bo2 zombies not as fun as bo1 are 3 things: leaderboards/stats, rank, and lack of longevity in the maps. a stupid rank emblem has created more rage quiters than anyone could have imagined. the stats also play into rage quiting. there just isnt much replay value in these maps. you have to grind it out till round 25 before the real fun starts. thats the problem with bo2.
and on a side note, i have ran into some modders on bo1. they are quiet fun for a bit.