I think the abstain option is a good idea because the alternative would be not voting. You could consider not voting as an abstain, but then again, do you really know if they read the proposal and decided they don't care about the outcome? or did they miss the poll in its entirety? If you don't have that abstain option, you really don't know.
If you set up rigid categories like I explained above, new users will probably be making casual polls which I don't think should require a minimum vote weight requirement, because casual polls shouldn't be actionable and only get a community opinion per se. New users who have a high balance in order to make the bigger polls, are obviously invested in gridcoin, and probably have/should have done their homework about what vote weight to select before making an important poll. Simply put, I don't think this will be much of an issue.
As for the recent developer compensation poll, I don't see this situation as the fault of this poll. If you add a clause like "if this poll does not pass, developers will continued to be paid $30/hr", then you're saying if it fails, part of the poll will be enacted anyway. Which makes my stomach feel weird to be honest. The problem is that the previous poll (the one that paid devs $30/hr initally) only stated it would be in effect for the next 6 months. What it should have stated was the $30/hr had no expiration, and we would have a poll every 6 months to review it.