I think that the OT rule shouldn't be there for a competitive event like a tournament in PRO, that's like wanting to make an Olympic game open to more people by restricting the amount of training an athlete can do.
A core component to PRO is its market, trading pokemon and farming money to buy pokemon is a fundamental element to the game, and no one (or very few people, for personal choice) ever paid much attention to the OT, considering only the “quality” of the pokemon.
Everyone in this MMO strived to get the best possible combination of ability/nature/IVs, that can be achieved through 2 different ways: hunting or trading. Since everyone knows that the spawn rates are specifically designed for a MMO environment (some pokemon are so rare that only few players will be ever able to obtain epic ones through hunting), restricting a tournament to OT-only pokemon really upsets everyone who focused and spent a lot of time into obtaining really good pokemon through trading.
A “tournament” is itself the definition of competitiveness, the best player wins, it's not something that should be designed to give a winning-chance to as many people as possible by providing an equal “disadvantage” to everyone.
The OT rule not only penalizes the veteran players without almost any OT pokemon left (because the longer you’re in the game, the more epic pokemon you get, the less OT pokemon you have because you realized that in order to get a good competitive team, trading is necessary), but also penalizes the less experienced players that focused on trading since very early in the game.
The OT-rule makes this tournament designed in a way that “lucky” people are given an enormous advantage, the one with the better legendary or the better luck in general will prevail. The ones with experience in PvP won’t likely participate by hunting a whole new team specifically for this tournament, given all the effort that they put into building a good competitive team already.
If the original intention of the event was to involve a wider amount of people, probably a better idea would be to design a different kind of event that gives clear advantages to lucky people and puts everyone in the same starting position, something like a hide and seek event or anything different from a PvP tournament.
Tournaments will be always won by people with experience in PvP and that are likely already in the ladder, like Olympic games will be always won by the best athlete that put the most effort into training.
That said, it’s just my opinion, and as a former staffer I’d like to see the community appreciating the effort of the current staffers that dedicated their time into making this event as enjoyable as possible for you. We can all post our criticism in a way that doesn’t demoralize the people that are working hard for PRO community (there is already someone who takes good care of constantly doing so, no need to add the community to that as well). Everything can be talked through in a nice way <3