Let's compare frontcourts to Western playoff teams, Ayton, Bridges, and Jackson really isn't undersized. The more I looked the less worried I am if that's the way the Suns go. Most of the Western playoff teams play a Center with 2 SF's, or a tweener Forward and a SF. There are few exceptions to that but our frontcourt would not be that undersized at all, especially after things get shaken up with free agency and the rest of the offseason. If Bridges and Jackson end up being good defenders, that will help things quite a bit. Those both physical players so they shouldn't be giving up much.
Frontcourts for Western Playoff teams that played a C and 2 SF's.
Warriors: Pachulia, Green, Durant (Of course, they're the champs but they played Green, Durant, and Iggy a lot in the playoffs, I don't mind the matchup of Bridges, Jackson, and Ayton against them)
Portland: Nurkic, Aminu, Harkless (Nurkic is a FA, their F's are both SF's)
Houston: Capella, Mbah A Moute, Ariza (Mbah A Moute is a free agent, they used Tucker in the postseason a lot and they also used Ryan Anderson, I'm not concerned with losing 2 inches in height to Ryan Anderson)
Thunder: Adams, Melo, PG13 (George is a Free Agent)
Nuggets: Jokic, Millsap, Wilson Chandler (Chandler is a free agent, Jokic & Millsap are staying, Millsap is an undersized PF though)
Clippers: Jordan, Tobias Harris, Wesley Johnson (They got small once they lost Griffin, DeAndre Jordan is a Free Agent also)
Pelicans: Cousins, Davis, E'Twaun Moore (They basically played 2 Center's and 3 guards, Moore, Holiday, and Rondo. Moore is 6'4. Without Cousins they went with Davis & Mirotic in their frontcourt)
Spurs: Gasol, Aldridge, Kyle Anderson (of course Kawhi would take Anderson's role)
Wolves: KAT, Taj Gibson, Wiggins (This is the only "traditional starting 5 in terms of positionally, KAT plays on the perimeter though)
Jazz: Gobert, Favors, Ingles (Favors is a Free Agent, so who knows)
Tell me what team will be able to dominate our frontcourt because of size? If Jackson and Bridges play tough, hard defense, we'll be fine.