RMSS and RMFRP had companions too and there wasn’t any power creep issues. Maybe some imbalances there and then but nothing a good GM couldn’t deal with.
Their goal was clearly to expand the game, not give more power to the players.
I think they did a good job with new classes, training packages, and spell lists. I would hope that skills are kept to a minimum because here is a place that complexity can creep up on you if you aren't paying attention, especially for arms-race type skills (e.g. mental assault and mental defense).
The martial arts companion in particular made some fairly deep changes, which I thought were good for the most part but I would like to see some of those become core. (E.g. very different handling of adrenal defense and martial arts ranks.)
Whereas, say, the Channeling Companion was full of good ideas but there is nothing in it that makes you feel like you need to go back and rework existing characters.
To be honest, I believe RM should have less skills, combined together to attain the desired goal.
Pick locks ? Lock lore + manuel deftness
Build lock ? Lock lore + related craft skills
Jam lock ? Lock lore + required tool or material
Detect trap ? Observation/awareness + trap lore
Disarm trap ? trap lore + manual deftness
Build trap ? trap lore + related crafting skills
Jam trap ? trap lore + required tool or material
Silent kill ? Wrestling to prevent the quarry from yelling and the body to slam loudly on the floor.
Ambush ? If foe is surprised and you succesfully stalked him, use weapon or anatomy skill rank to modify crit roll
And so on…
You usually manage for greater variety in action and possibilities when you set a limited number of mechanics that can interact together rather than setting a lot of mechanics that can’t. And setting a lot of mechanics that can interact prevents you from keeping track of the action and results in redundant mechanics. The later is RM’s problem.