My experience- the T-47 is effective if you have a plan for using it. The combination of speed, firepower and altitude can hit the enemy VERY hard in the first round or two, seriously hampering their effectiveness. It’s speed will easily let it cover 14” of movement with 18” of eligible targeting beyond that- that 42” of battle field which aren’t safe in the first round. In a Long March, that’s not going to help much, but any other set-up configuration will let the T-47 line up an attack on round one. Give it long range comms to keep it flexible as long as it lives and pummel the enemy with air strikes.
Anecdotal- first game I played, the T-47 wiped out all but the unit leader from a Stormtrooper unit. That removed the guys protecting Veers. Barricades are hard pressed to give cover against something as high up as the airspeeder.
Last night, while the speeder didn’t do as much damage on round one, it still took out half a squad on round one. And it got close enough to prevent the HH-12 from being useable. It was dead by round three, but it dealt a lot of damage before that.
Plan for the speeder to be an early tool to limit enemy capability- lots of attrition. If the enemy has fewer troopers than you, you’ll have better flexibility to move where you need to for objectives. If you force him to cover, imposing suppression with attacks and/or moves, that also gives your forces more flexibility.
Add to that the T-47’s armor and cover, making it problematic for anyone without impact, and the airspeeder becomes apparently useful. Maybe not the most point efficient, but also not as bad as some claim.