Fred, I'm not saying they aren't disadvantages to wet cells. Some of the issues you bring up (acid leaks, vapors) etc, are certainly real issues, but mishaps are very rare in a proper installation with the correct charger.
As far as sealed AGM outperforming flooded cells...nope. Pound for pound, good quality wet cells have more capacity. That's why big boats like yachts and pleasure cruisers still use banks of the old fashioned, very heavy duty flooded batteries from companies like Rolls, Trojan, East Penn and Surrette. Most will last a minimum of 300 cycles, and some can last thousands of cycles.
Here's some capacity comparisons by weight (all amp hours at the C/20 rate):
Optima Yellow Top (AGM/sealed deep cycle)
65 amp hours/44 pounds = 1.48 amp hours per pound
PowerTroll Group 8A27 (AGM/sealed deep cycle)
95 amp hours/63 pounds = 1.50 amp hours/pound
Rolls 27-112-XJ (flooded deep cycle)
112 amp hours/57 pounds = 1.96 amp hours/pound
Trojan 27TMX (flooded deep cycle)
115 amp hours/59 pounds = 1.94 amp hours/pound
AGMs have their place. If you put a premium on no-maintenance, maximum stored charge life, or need to use them at a funny install angle, they are top notch. If you want maximum amp hours in a typical bass boat-with-an-onboard-charger, quality flooded cells win.