The benefit of specific platform support (RouterOS only works on X86 and RouterBOARD(TM)) is that we have control over hardware, and on RouterBOARD - the software is guaranteed to work.
[ggnnnhh... can't help myself posting... after this....gnnh...]
Well, that's the theory, isn't it?
Real world sometimes is disapointing.
I agree with normis. Having a small and consistent set of variables makes software easier to develop and maintain.
On the other hand, the underlying linux system runs very reliably on a huge number of platforms. Other developers are doing the work on the kernel, drivers, etc.
I get Mikrotik's business model though. There are only so many options required at each price or capacity or form factor target. Their model scheme works well. 493<493AH<493G. The MIPS CPU in these devices has been so successful that it has helped build mikrotik into the vendor they are today. MIPS is going to be around a long time, it is a proven CPU design and the SOCs available on the market are rock solid. What would be the point of a 493ARM? MIPS is in FAR more routers than ARM.
ARM is not better than MIPS. They are different, but MIPS definitely holds it's own. The true strength of the ARM platform is really the I.P. licensing model ARM Inc uses. Since Mikrotik doesn't do any of their own CPU designs and instead uses existing packages to build their products, ARM doesn't really offer anything that the existing line of MIPS chips doesn't already offer.