Re: I would make the move...
Yes, but it doesn't help at all. A&A won't allow 1Gbps of traffic so I still have the complexity of having to split traffic between the two routes (important traffic via A&A, bulk volume traffic via GC) and I lose the backup of having two lines, going to two separate ISPs (I would have to keep my existing backup line and end up paying three subs).
I may as well keep the A&A line and the GC line completely separate, and avoid any potential issues with the L2TP traffic.