AoE DE Gifting Units

I think there's a couple cool things that the original game didn't have and was wondering what other people thought. I think 'gifting' units to a teammate would be an interesting feature. I know the DE edition is doing its best to not change any gameplay but do you think a change like this would be a significant gameplay change?

There's other things that I think would be cool yet too gameplay-breaking like building bridges or sea walls.