Is Occam's Razor a logical fallacy?

[pbrower2a]

The simplest explanation consistent with the established facts is most likely to be true and must be accepted as the best explanation.

The Copernican theory of of a heliocentric system is far simpler than the Earth-centered universe of Ptolemy. Indeed, the Copernican system was accepted even when it was less precise.  Don't laugh! A Ptolemaic system can be as precise as the current one with about 75 circles of movement, some of the subtlest accounting for relativistic effects. It's just too complicated to explain. 

Don't add pointless fluff to a perfectly good theory.

[pbrower2a]

The simplest explanation consistent with the established facts is most likely to be true and must be accepted as the best explanation.

Of course, that is a statement rather than an argument. On what ground are we to say that the "simplest" explanation is most realistic?

It's an entirely arbitrary assumption.

Newton's laws of motion are straightforwad enough.  They are easily expressed, and adding anything to them  muddies them. Kepler's laws of planetary motion? Likewise.

For real complexity -- and doubletalk -- try astrology. It makes astrophysics and relativity look simple by contrast.