I've had problems on the last 2 servers I've been on (welchs and dads) and I'd have to agree with you that the issues you're experiencing may partially be due to poor, inexperienced administrators (case in point being how poorly managed the mail servers are, but also DreamHost's lack of doing something about high cpu usage until I've reported it). Overly crowded I don't see so much as an issue at all, though rogue users (consuming too many resources, etc) are definitely a cause behind many of the difficulties not only we as customers experience, but also for administration in their attempts to deal with such users (which is never an easy task).
That said, I strongly recommend you work with support over the issues you're experiencing. I've made sure to include as much information as possible in my emails to support and I've emailed them as often as possible when I see something "funky" going on. I've been very happy with the responses I've had thus far from support, though I'm still considering asking to be moved yet again to another server, as it appears there is something seriously wrong with the 'dads' server currently... the few "rogue" users they've been trying to deal with aside.
"Bugging" support I don't think is really an issue - as (in my mind) you're helping not only yourself, but probably many other users on your server that, like you, feel "bugging" support is a last resort option. Bug the hell out of them I say!
They seem to enjoy it (as long as you're nice about it) at the very least
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