Your points are valid, and certainly the texture of the board plays a role in how one goes about playing any hand. And I agreed that the hero should raise this particular flop for the reasons I outlined, but I will also say that in a smaller sized pot on this board, slowplaying has its merits, I am not saying that one should always slowplay this flop if the pot is small, what I am saying is that when the pot is small, (the size where just calling the flop will not allow a gutshot draw to call correctly) then smooth calling the flop becomes a reasonable alternative to raising the flop. Now there may be other factors that might lead you to raise this flop regardless of pot size, but thats not really my point. My point is that in a small pot smooth calling the flop becomes an acceptable strategy, but in a 11sb pot such as the one in this thread there is only one right strategy IMO, and that is to raise the flop for the reasons I mentioned.
I will also mention that if pot size was very large, like 20sbs or more, I am smooth calling this flop every time, since a flop raise will not protect my hand from a gutshot draw. I would call, hoping the original flop bettor would bet again on the turn and then I would raise to force the gutshots to fold correctly or call incorrectly.
So in a small pot you have flexibility, raising the flop and calling the flop are both acceptable strategies. In a large pot, raising this flop is the only acceptable play, and in a very large pot, calling the flop is the only acceptable play IMO.