While it is a good idea in theory, I think it'd be a bad deal in practice and execution. Some users may need help and come here to seek such help, and may not have the knowlege to fill out the specs to what we'd consider "helpful". While this may lead some of you to think that, if that's the case...they don't need to be here or something along those lines...in the end this place is about helping...and while in help seeking threads by new users I have explained and asked a million times about filling out the System Specs, I don't know if requiring it before the user's account can be activated is the correct way to go about it.
Considering System Specs is more of a feature than a necessity, I just don't forsee making it a requirement for having a membership here.
Maybe a few links in the e-mail for verifacation to explain what System Specs is and recommending it get filled out or system specs be added to the Signiature would be a good idea, along with links to some of TPU's guides for assisting users in diagnosing, overclocking, software and such. That way they already have their hands on material to help them become more knowleged before they ask a question that may have been asked 1000 times over, I think that would be a better method, though the impact of it may not be huge, I would not necessarily want to see TPU's future members be discouraged from joining if they don't understand how to fill it out (diversity...some people may just not understand, we're here to help them...but can't if they can't post correct?).
I say verifacation E-mail, or maybe an Introduction to TPU page when they click the account activation link that has instructions on how to fill out system specs with demos (images) and same for Signiature, along with some important links to articles, rules, guides, etc. There's a million different ways this could be done, in the end, it's up to the staff, but I still think it's a good topic to be covered, I just dont' agree with the OP's solution for it, I mean no offense by it, and hope you take none by it. There could be a lot of great ideas that stem from this thread that could eventually lead to a more dynamic introduction method for newly activated users to gain a little bit more knowlege about what they have before they ask us how to fix it.