I have similar feelings on ID:R.
All the Alien tech and stuff they gave the humans just deflated the tension for me. I'm not really interested in seeing a future earth battle aliens. I want to see current earth with the limitations we have fight aliens.
Plus I don't buy the fact that, supposedly, humanity, in just 20 years, were able to allocate huge R&D resources, break down and reverse engineer the alien technology, and manufacture working helicopters, space ships etc.
All this while most major cities in the world were blown to pieces, probably crippling manufacturing and infrastructure.
I thought about what I would like to see, before even seeing the film, and where I would take the 2nd installment if I had to brainstorm a bit.
What I came up with was probably too close to "District 9" or "Battle Los Angeles" to be worth doing, but I think the best way to make a 2nd ID film would be to set it as us fighting the aliens that would presumably be left alive on earth. This aspect I was surprised was actually dealt with in the movie, but those aliens were either just rounded up easily and held in a prison of sorts, or we saw skulls from ones previously exterminated, and it didn't really make any difference to the plot.
I would have wanted a still crippled earth, as we still would be exploring and finding out more about the aliens, to find there is still a threat from aliens left on earth. You could still have a queen alien, if you wanted that, emerge from a bigger ship that landed in a distant area on earth that we didn't hear about in the first movie, and revelations could be made about plans the aliens have to finish the job, or do something else. I think that basic framework is much more interesting and the earth being still very crippled would be interesting to see.