Johnboy 35, a direct answer to your concern is, that relying on a LPCM-capable amp is most likely a future-proof solution.
First of all, supporting LPCM sound on disk is a mandatory feature of all Blu-ray players, and it would be strange indeed if it were not supported in the long run in the player-amp interface.
Secondly, Blu-ray profile 1.1. actually favours the LPCM interface, because in PiP commentaries, for example, you may want to be able to mix two audio tracks. I am not aware of any player being able to bitstream two HD soundtracks simultaneously or of any amp being capable of receiving, decoding and mixing two independently bitstreamed HD soundtracks. You therefore have to rely on the player to do the mixing, which is most naturally done in LPCM, and this implies that the player needs to decode the HD soundtracks, following which it is most natural to send the mixed output as LPCM to the amp. The only thing to look out for is that the player has all the HD codecs that are required for proper HD decoding. Of course, anything can change, but moving the mixing funtionality from the player to the amp does not appear to be currently in the works.