You're never going to be using every one of these abilities in a single fight. Some, I would wager, will be rare picks which you only use once or twice, alongside your base 'set' of abilities (likely consisting of Icy Touch, Plague Strke and some sort of big hitter).
Compare the amount of abilities to the amount of spells any of the spellcasters - even the spontaneous ones like a Sorcerer who will usually have smaller portfolios - will have on hand by level 20 (assuming we're including all the abilities). I'm quite sure that - especially in the case of Clerics and Druids - the numbers don't even compare.
While I do agree that it might be a bit of an arse for a DM to have to look over all the abilities, I also think it's far too cool a class to dismiss out of hand because of it, especially when the core classes have drastically more 'abilities' available to them. Orisons+1st level Cleric spells in PHB number 37 in total, not including domains. That's how much they have available at 1st level!
Edit: Kinda Swordsage'd, point still stands though