GPS conclusion
I had some time this holiday, meet up with my cousin who has the same phone, same D803 (okay I am on Rogers, he is on Bell). In addition, I compare it to my brother's Optimus G, and the conclusion is clear:
Using AnroiTS inside a house, neither G2 will give any signal whatsoever. However, with my brother G, he was able to pick up around 6 to 7 satellite albeit weak but still able to get a location. I had them on for 5 minutes, still nothing. Looking at other who changed 3 phones and same issue, I think it is crystal clear to me it is a poor GPS antenna design which has led to this problem. And when you look at N5 user having similar issue, I think given the similar design, we can all conclude it is nothing we can truly do about this.
The funny thing is when speaking with my cousin who live in downtown area, (with taller buildings and what not) and I live in the more rural area with few high rises, he praise that the GPS is good and fast locking. In some case, it does lock very fast, I experienced it myself, but it is hit and miss. However, the accuracy of this GPS is very very poor mainly because the GPS signal is weak. So from 2 different user, we have 2 experience and I prove the phone are not one better than the other. Mind you, we are both technical people so it isn't like he doesn't know what he's talking about, he may not be a Android freak like myself and modify things and what not but I think why some people believe it is okay is because it sort of work marginally for them.
After that test, I shell out $100 for a GPS re-radiating device, I am really hoping this will solve the problem in the car at least which is where I use it most. When I get the unit, I will report back and let other know if it improve it (which I think it should) cause there is nothing defective about the s/w or h/w, just the antenna sucks.