Some way to combat multiple roles would be very welcomed in ranked by a lot of players I think, but there are ways to go about this beyond hard role restriction if this is not something your team wants for the game. Obviously most suggest a role lock to limit teams to 1 of each faction and then the 4th can be any (or the 4th has to be a Meridian or Aeros only by some peoples suggestion). BUT another way to do it if role locking is not in your vision as it limits the players ability to choose the guns and loadouts they enjoy best (it's personally not in mine) would be to limit the effectiveness of utility (the ult and the ability) in some way scaling with if there are 2, 3, or even 4 of that role on the team. I'll leave the numbers up to you if you ever did go down that path, but some simple examples could be that every additional Sabrask (for example) increases the cooldown of shield by some amount, say 10 seconds. Could also reduce the uptime of the ultimates for example each additional Meridian shortens the uptime of the infrasight by 10% of something akin to that. As for the ability, you could leave the harsh locking to this area, such as not limiting teams to only 1 Sabrask, but if teams do run Sabrask only a maximum of 2 can utilise a specific ability such as smoke grenade (so if a team had 4 Sab, 2 could run smokes and the other 2 would have to choose the grenade or prox mine. Teams would likely do this anyway but limiting would still be effective particularly for hotzone where 4x smokes and 4x shield can be very boring). Meridian time dome and healing grenade should likely receive the same treatment, as well as the Aeros stun but the Aeros self heal and porta-portal likely don't need to be limited as they are more for personal playstyle than team buffing or crowd control.