Well I am able to play WoW on my hotspot and barely burn much data. However, my experience with GW2 is that just the update downloads during startup (of which Anet does a lot) add in significant amounts of data and stress the data package. I have no way of finding out how much data load a given update will impose, AFAIK. This makes me leery about the game on a hotspot.
Which is unfortunate because I love it and now rue needing to be on a hotspot.
Not really sure what I'm asking for here other than any kind of contradictory information on update data loads. To me they seem like a lot, but perhaps they are not? I appreciate that Anet does so much updating. Just not sure I can absorb it. Nor do I know of any way to check online as to how much each update is (which makes sense given that the vast majority are on broadband).