I'd never even thought about either of those things! I very rarely use summons and didn't even do so very much in DKS (as with my dog in DA:O, I called him Dave; both were called Dave and both had a rather obscene habit of urinating on random stuff. Hmm.) but it sounds like something I really need to explore further.
And I'm not sure why I hadn't considered using the DK as a ranged fighter: I guess I just have this ingrained expectation that a DK's approach to any situation is "hit it until it dies", which suggests an enthusiasm for mêlée and nothing else. Which is obviously wrong.
Well I'm still aimlessly wandering around the imp world and not seeing the pointer for wherever the alchemist is hiding, so it's about time I looked at one of those guides you linked to...