i use my 450 xc-w for commuting and road trips (as well as single-track, hare scrambles, offroad exploring, etc. etc.).
i rarely ride my DRZ anymore, except at night (because the KTM stock headlight sucks...that is one real issue--but it can be addressed).
i've done 300 mile road days on the xc-w and loved it. the bike is so ridiculously fun to ride. for me, i just need to wear padded bicycle shorts, but the seat is probably not for everyone. however, you can always replace it with a more cushy one.
the maintenance is no big deal.
it is a way better bike in every way than either a DRZ or a WR250R (i have ridden one) except for maintenance intervals (but they aren't bad at all) and the headlight (which, on mine at least, sucks for riding on the road outside of a lit up city at night).
the KTM is better on the highway, it is better in the city, it is better on a MX track, it is better on quad trails, it is better on single track, etc. etc. better by a lot.
if you can afford it, get the KTM. if the price of a new WRR is the limit of your budget, spend the price of a new WRR on a used EXC/plated XC-W instead. seriously.