> Holding things by pointer on the other hand actually does let you prevent the includes since you can just forward declare in the header, but it's an indirection :-/

And it means you now need to deal with raw pointers, which often isn't optimal or preferred (over say references for example).

At least we'll get modules soon. That should reduce the need for some of these workarounds that are really mainly used to reduce compile times, and not to improve the code in any other meaningful way.