unfix8r:
Who cares if you have 80# (like I do) or 100#, if you can stay comfortably on the surface. What are you worried about? Drag? Hah!
Too much is definitely better!
I disagree.
Firstly, having a huge wing DOES cause an amazing amount of drag underwater. It creates a lot of resistance, making it difficult to keep up with your buddies while you're diving. To keep up, you have to work harder, and so you breathe heavier and thus use your gas faster. Additionally, diving in a current gets near impossible because of all of the drag you have in your rig. Remember, a freediver equipped with fins can only sprint to 4 knots underwater... It's much less with gear on. In fact, in a recent Rodale's Scuba Diving magazine, there was no diver tested that could exceed 2.8 knots underwater in a single tank and wetsuit. None of them were able to MAINTAIN more than 2.2 knots, even at full effort. So yes, drag plays a huge role in your diving. A little more streamlined can go a long way in terms of gas consumption, effort spent, the speed at which you can cruise, and in the case of a current, your ability to stay in one spot.
Secondly, large bladders tend to be "all over the place," and a gas bubble within tends to travel to the point which is furthest from your body. So... Large bladders tend to tilt you one way or another, in a situation I called "opinionated BC's" in this article:
http://www.DeepSouthDivers.org/homebc.html
Lastly, large bladders tend to "wrinkle" when you're diving with them, trapping gas bubbles inside... So they're more difficult to dump completely. To compensate, divers often wear more weight than they need to, once again adding to the effort spent while diving. (Not to mention that typically the weight isn't well - placed, making the "opinionated BC" problem worse...)
In short, yes... Having too much lift can be just as bad a problem as having too little.