I think it's important to note that the main limiting factor, and subsequent long recharge times, is not so much limited by the FLA's (or any other type battery) themselves, but the charger that is being used.
Using a programmable, heat adjusted charger will dramatically reduce charge times and improve overall battery performance. Prior to the AGM's I'm using now I ran T105's that I charged at 14.6 bulk, and 13.5 saturation. I got 9 years out of that bank (full-timing and better than 95% boondocking)... and going strong... when I made the switch to AGM.
Where most baseline chargers only deliver a timed 13.5 bulk.. no wonder it takes forever.
The other issue is typically that, even for stock converter/charges that deliver 14.4, it's rare that your batteries are actually getting the full charge rate due to under wiring. So called "smart chargers" greatly improve overall performance, but you're still not going to get the full potential/life out of your batteries.
Granted.. the programmable heat adjusted chargers cost quite a bit more, but they pay for themselves by keeping your batteries much healthier for much longer.
Like Cam was saying too, limiting your charge cycles to 80-90% on a regular basis is pretty harsh on your batteries. One other approach to help avoid that is increasing your battery bank so that your discharge rate never falls below 80% SOC. Your charge times will decrease and your batteries will last significantly longer.
All that being said... for most folks that camp just a few days or weeks out of the year, it's difficult to justify the additional cost of a larger battery bank and programmable charger. Even for those though, investing in a "smart charger", at least, will make a dramatic difference in terms of charge times and battery health.
* by programmable, I don't mean those chargers that allow you to select one of several pre-programmed charge profiles. Programmables allow full custom settings... (ah's, soc levels, temp comp rates, etc)