Not quite as pretty
High front end
I'm not sure that most of those are right.
Less nimble is very subjective. I still love my 26" bikes because they're definitely more flickable (for want of a better word) but then even on really twisty singletrack, the 29er never feels too slow in the steering. So, it may be 'less nimble' but not to the point of it being a negative.
Heavier wheels - yes, this one is correct. But then you're repeating it on 'heavier tyres and slower acceleration'. In reality, I seem to be pretty much the same speed on my 29er as on my 26" bikes so I wouldn't be worrying too much about this unless you're a world class XC rider.
Not quite as pretty - well that depends. I think my Swift looks great but then it's an XL and looks very much in proportion. I know that many (especially the 29er evangelists....) say that my 26" bikes look too small so...
High front end - this can be an issue, particularly in smaller sizes but isn't a fundamental issue. I'm actually about to raise my 29ers front end a touch as it's very low right now.
Anyway, I wrote a review of my Swift some time ago that still holds true now I reckon - it's not more or less fun, just different. It's not quite as BMX feeling but then the confidence that goes with that means that I am encouraged to do sillier things on it which is fun.