And, in all honesty, this forum doesn't look very professional to begin with.

I think it does, it has a clean interface, it is readable, it loads incredibly fast, it can search through old posts, with multiple terms and date range, you can even hide signatures and everything. And, I haven't seen this on many boards: the threads don't run away, they stay where you put them!
So, what's missing or faulty here?
- It doesn't have all sorts of animated borders -> Great, please keep it that way
- There's less than 2000 different colors in use -> Great, please keep it that way
- It doesn't let me bump my threads up -> Great, I hate those people anyways
- Dunno if you can use images as signature, I think not, thanks to the hide signatures setting I don't even need to know, I don't miss it anyway.
- There's too few smilies: maybe, but that's not a reason to change the entire board
- Default search period of 1 week is way too short -> yes, but I don't believe that can't be changed with UBBThreads.
- Older, still active posts can sometimes disappear to page 2 -> yes, this is a problem