Hello!
I don't think that Konqueror in its current state is usable for most of the "modern" Web (even Wikipedia!). Hell, a lot of modern websites are actually hardly usable even with Chromium-based browsers (which are the unwritten standard for the modern Web) unless you have lots and lots of RAM to spare. Of course Konqueror's own KHTML/KJS engine is very outdated and has little hope IMO. So, creating a WebKit or WebEngine port for TQt/Trinity seems to be the better solution. But I don't think it's coming anytime soon.
I also use SeaMonkey both for Web and E-Mail (the latter mostly because one of my accounts requires SSO login), but I do use Konqueror for some simple web pages. Still, having a modern web engine is very important, since all Trinity's application will be able to make use of it. KlamAV is indeed a good example, since it uses KHTML/KJS to show web-pages, and does so with quite a big difficulty.
-- Mavridis Philippe