The M14 has been called the "Perfected Garand" with justification.
The Garand's flaw, if it can be said to have one, was the en bloc clip, which was essentially foisted off on Garand by John Pedersen -- all Garand's early designs had box magazines.
The flaw in the en bloc clip was its complexity. Strip a Garand and look at all the parts necessary to receive the clip, lock it in, eject it on the last round, or allow the shooter to eject a partially empty clip. Gunsmiths who know the Garand talk about "timing" -- which is getting all those complex parts to work together properly.
The effect of this complexity was that only Winchester and Springfield were able to manufacture Garands that actually worked -- other companies tried it, but most of their production had to be reworked at Springfield. It wasn't until the Korean War that other companies were able to manufacture quality Garands.