I'm a little confused - are you talking about the 1.9" Patagonia tire mentioned in the OP?
There's nothing wrong with the tread-to-void ratio, there... and there's very deep cuts that will allow flexing of the tread blocks as well. There's loads of tires out there with similar ratios and less siping and/or deep cuts.
And this tread in the newest RC4WD compound should do quite well - they are extremely sticky.
Not every tire design is necessarily meant for every terrain out there. I'm planning on picking up a set of these in the not-to-distant future, although I really need to slow down on tires because I have too many sets already...;-)
The new 1.55" Goodyears are definitely meant for somethin' else entirely - these have seriously shallow tread, but some people want these for pure scale appeal, I suppose(?)