Grit is some what nerfed because his Infantry are usually used as a shield for his indirect units and aside from Artillary, his units are pretty expensive. Rockets, Battleships, and the different Anti-Air units are pretty high in costs.
Additionally, one of Grit's advantages is having his "tanks" be 6,000 funds, which means he normally get an extra infantry when buying his "tanks" while everyone else can only buy a tank. While 1,500 Infantry affects everyone, grit now has to wait an extra turn to get the extra infantry. In a way, this also negatively affects Sturm (AWBW/Original), Kindle, Sonja (in FoW), and anyone who uses Indirects more than usual.
Anyways, I think APCs could use a buff, but have a price buff instead.
One of the reasons why APCs aren't used that much in the capture phase is because most maps have plenty of properties around your base to get on Day 1-7. By the time you do, your infantry would already be in the center or other fight areas.
The only options you could have for the capture phase would be to have a map that has multiple paths, otherwise the only option (if you know what you're doing) is to take the most optimized route (which usually is forgoing the APC until later on, where the APC becomes a Mech transporter).
The only other time I can think of where transports would be viable for the capture phase would be on massive maps with spaced properties, and for Tcopters/Black Boats, little islands with several properties on them.