I've yet to feel any fatigue while using reds. I've felt a little extra resistance on days when I have typed massive amounts, and then played games, but overall its been extremely easy to push these keys. Getting used to keys that are this easy to push can require quite a bit of practice. I think that most people would consider these keys "just right" or a "bit light" and there are some people out there who really like stiffer springs (60g to 70g).
Accidental presses is very real with red switches in my opinion. That is probably there one weakness, and probably a good reason for some people to pick blacks still for gaming. Although, reds will probably always be a good gaming/typing switch. Brown with the same spring will probably be more of a typing/gaming switch, and remain more popular overall. I see reds staying with gamers (mostly), and blacks will be popular still for gamers because they are linear.
Topre switches I know can be in the 30g range, and I know some people think that is too soft. I really don't think reds need to be any softer.