I think the new power armor (T-60, right?), which is more like a personal mech suit/armor, may be more limited than the older T-45s and T-51s. I imagine that if/when we run across the standard gamut of power armors* (T-45, T-51, Enclave Advanced, and Enclave Tesla) they'll have the same mobility they've always had.
So it's entirely possible that you won't be able to march across the wastes in your customized T-60 armor. I mean, it doesn't really seem like the sort of thing you'd use all the time. Then again, that does seem to run counter to the exploration-based gameplay that Beth loves so much.
Perhaps there will be some quest/questline that would enable the T-60 to go everywhere. You know what? Yeah, that's how I'd do it. I'd put the macguffin that let's you use the T-60 whenever towards the end of the main questline.
*Not based on the T-60 frame that the protagonist has. Unless they're retconing all the armors. In which case I'd hope there are no limits.