As long as whatever doctrine is taught is firmly grounded in scripture. Paul marvelled at how quickly the Galatians slipped into error. They began teaching as doctrine the commandments of men.
He answered and said unto them, Well hath Esaias prophesied of you hypocrites, as it is written, This people honoureth me with their lips, but their heart is far from me. Howbeit in vain do they worship me, teaching for doctrines the commandments of men. For laying aside the commandment of God, ye hold the tradition of men, as the washing of pots and cups: and many other such like things ye do. And he said unto them, Full well ye reject the commandment of God, that ye may keep your own tradition. (Mark 7:6-9 KJV)
This whole Mary thing is based on tradition and yet these people act as if the fact that Mary might have had other children is somehow centrally anathema to the gospel. They focus on Mary instead of focusing on Christ. They elevate Mary thus diminishing Christ. They focus adoration and veneration (which is objectively indistinguishable from worship) on Mary when the commandment of God is that you should worship God alone.
Other than that tradition is just peachy.
Flame suit on.
One example of "diminishing" Christ is think of Him as someone Who would not want His mother elevated.