I'm an altoholic myself as well. In this game, and in every other MMO I've played over the years.
I like my Sage and Sorcerer, because they play very similar to my Priest back in my WoW days. For now they are also my only 2 level 50's.
My Mercenary and Marauder are level 43 and 42 respectivelly. My Shadow is now level 34 and my Scoundrel is 26. I've never been fond of stealth classes in other games. Usually play the ranged healer type. But after toying around with my Shadow I've started to enjoy stealthing around. But I felt something missing. Since I'm a healer at heart, and not a tank or DPS.
So the game gave me a solution
Sawbones specced Scoundrel. And boy is it fun
Might not be the fastest killer around, my Shadow eats enemies for lunch, while my Scoundrel takes awhile. But the combination of stealth, some really nasty abilities (dirty kicking mobs and then back blasting them with a shotgun) and the ability to heal makes it a win-win combination for me. Looks like I have finally found the perfect class for me. It took me over a year to get there, but that's OK
So my recommendation to you would be to make a list. Put on it everything you want a class to be able to. Then go look which class most closely resembles your wishes. And go play that.
Just stop deleting characters. I mean I haven't played my Marauder and Mercenary in ages. But they are still there and at quite high level. I have 12 character slots, and I only use 6. So no need for me to go trash stuff.