I would like to see reclaim happen at speeds based on the amount of resources. So if you're reclaiming 100 mass worth of broken trees, that should be about as fast as 100 mass of dead tanks or 100 mass of rocks. You would have to have engineers take less time, basically zero downtime, between reclaiming different targets. That would reduce the need for manual reclaim orders, because attack-move would be nearly as efficient. If you could shovel 100 mass into your face just as fast with attack move as with manual reclaim orders there would be a lot less clicking.
Another way to fix it might be to have attack move always work like factory attack move (where the engineer walks to the waypoint and then reclaims at guard range, instead of traveling down the path acting like it is on patrol). You could quickly queue up a series of attack-move orders so you don't have to babysit engineers and constantly adjust their orders to get the benefit of factory attack move. FAM can be at least as good as manual reclaim orders, so in most situations, manual reclaim would be unhelpful.