I expect "baseline competence" will quickly become incompetent in messageboard debates because the PC who is at or near the baseline isn't optimized enough.
The best way to minimize CharOp is to simply encourage a game culture of creativity over power building.
In my view, if you don't want character optimisation in one dimension, the game should be designed so as not to reward it.
There are multiple ways to do this. One well-known option is to put mechanical burdens on all stats, for example, so that dumpign one stat will weaken the PC.
A less-frequently discussed approach, but in my view just as important, involves encounter design and adjudication. If a GM runs encounters in such a way that players who aren't optimised for a particular activity nevertheless have a good reason to get their PCs involved in that sort of activity, the effect of optimisation will be reduced.
A simple example of this involves the idea of the "face" PC. If the GM doesn't want the party face blitzing through all the social encounters, then the GM needs to design encounters that give the players of the other PCs a reason to get their PCs involved in social activity - for examle, NPCs try to talk to them, and will leave their PCs looking stupid (or otherwise suffering some detriment to their fictional position) if those non-face PCs don't start talking.
This also relates to the idea of consequences for failure. The less likely it is that by failing a skill check you will render your PC's situation unplayable, the more likely it is that you'll have a shot at doing stuff even when you're not expert at it.
So failed combat can mean capture rather than death. Failed climbing checks can mean you take longer, rather than you fall. Failed social checks mean that the NPC ponders your wise words long, but in the end take a different view, rather than that the NPC thinks you're an idiot who should never have opened his/her mouth. Etc.
Conversely, the approach to optimisation and "having a go" which says "let's ignore pushing the mechanics hard, and play as if the mechanics weren't what they are" doesn't do much for me at all. What's the point of having action resolution mechanics, and PC build mechanics, if the players aren't expected to use them?
(And to be clear: I'm not talking here about unexpected and overpowered synergies that are the inevitable result of long lists of complex game elements. The solution to these is gentlemen's agreements, house rules and/or errata. I'm talking about whether or not players are allowed to take the central mechanics of the game out for a thorough spin.)
(I suppose "bashing" fits better, and keeps each one more distinct, but it sounds wimpy compared to the other three. 
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