HARP, why not RMU

[katastrophe]

I asked a similar question in the Rolemaster forum. Now that RMU is out, with its similarities with HARP, are any of the HARP players, GMs, writers, interested in a switch to RMU. If so why? And if not, why not?

Personally I have several of the HARP books (rule books and adventures) and like some aspects of HARP (particularly the magic system) and dislike some others (mostly the combat), but it's a very playable system. Overall it's either a simpler RM or RMU could be seen as Advanced HARP.  So I'm curious why HARP players writers etc are not switching to RMU.

Thanks in advance.

[GrumpyOldFart]

Two words: Spell scaling.