I would think it would be better to adjust the biggest factors that make ranged ADs ineffective in dominion and then do tuning rather than tuning first.
The mandatory summoner's aren't always what an AD wants to have, and I haven't found a particularly effective solution to that yet. No AD carry really wants to take revive... they benefit far less than tanks and bruisers from taking it.
The game pacing/teamfight dynamic is not quite right for them. ADs are picked for the lategame, and get there in SR by farming with a support until they are valuable additions to the team, and usually become at least somewhat valuable before major teamfights. In addition, fights happen infrequently enough that they have an extra escape spell from flash (burning a flash is helpful, but if you lane well, you should have flash for most teamfights), and having 5 people in a fight instead of 4 gives you that much extra power to peel for your AD with CC or lay burst on the offender.
However, in dominion, we just throw the ADs straight into team-fights with one less person to help them, with poor summoner's, less escapability and expect them to have a valuable contribution to the team early game. This breaks the legs of a lot of the ranged ADs in the game that are more affected by these factors.