Imagine working hard for months to make set for pvps in server then another newbie comes to PvP u with full set which he never worked hard for? Nop.
We need it to be in our servers than ptr.
If devs do like you say here not only they will drastically decrease the amount of the participants (since most of players have max q7 or q5 sets, which are ok for war scenarios but against q10 set in pvp where you also need to have some sort of luck along with skills is a no match) but also they will make community overall feel bad - as if this competition is only for "better ones".
Don't get me wrong here, like ok I get it you worked hard and spent a lot of money for your q10 set and thats totally fine since it's your business, but honestly 90% of all players that have q10 sets on live servers are either bought acconouts or opened them in Argentina/Turkey IPs for cheaper gold coins.
The game is already strongly P2W and that's fine also as long as devs provide us satisfying content and updates.
Therefore at least in my opinion this competition should be held on ptr where everyone has equal rights to win. I dont understand why are you concerned about new players tbh, as you said they now little about how pvp works in this game so they shouldn't be a threat for you if you intend on winning first prize.
We play the game to have fun (I'm not talking about ill addiction) so let everyone enjoy it on equal rights.
If you are still feeling bad about the topic of q10 clothes in live servers - you are already highly benefitted from it - it gives you better chances on claiming and reclaiming buildings and also it gives u huge boost for hunting.