I would say go with your original party combo, cleric included, if you like the idea and style of that party. It's a roleplaying game in the first place. You can make it work and you will have fun with it, no matter whether it's the perfect ideal super trooper party combo or not. After all I assume that you want some challenge as well and not just rush through everything.
If you enjoy that party combo, play it. It is definitely possible!
Also, there are a lot of skills for each class so you can mix and match each character's skills with what fits best for the party.
