Thanks for the ideas. While I agree with you that desktop IDE is a good place for design and architecture level reviews, having a lightweight web "IDE" will be beneficial as it does not require you to switch your local workspace to particular revisions for review.

Also I often find myself need to copy code from some old revisions, in that case, I just visit our web "IDE", find desired revisions with revision search helper, and open desired symbols to copy relevant code out.