Well the tough part for some of us like myself is that I have never seen in person a red dot with the buis mounted in front. I handled a sig p320 with the factory Romeo and it was OK. Because everything on it Co witnessed, it just felt like a red dot painted on the front sight. It's pretty much like having a front tritium night sight but in red since your always gonna have the habit of aligning the rear and front iron sights.
I wish I could handle all three red dot options in person. I'm starting to think of going the same route as OP, red dot with only front stock tritium suppressor sight.
An important point about RDS pistols from my own experiences... I was big on cowitnessing to begin with but, really the advantage of the dot is that it is on target
wherever it is in the window. Cowitnessing is nice, and I do like have BUIS there in case of a dot failure and also to help align the gun on presentation as I always have BUT the dot is a game changer for fast, accurate shooting irregardless of cowitness as long as you don't go wild and forget trigger control in the excitement!
I am still very much of the mind that, for a defensive gun, front and rear irons should be considered a requirement - regardless of placement in relation to the RDS and regardless of whether they provide 1/3 lower or true cowitness.
You lose a lot of ability to orient the gun at distances where sights are needed without both sights, after all. Try shooting an irons-only gun with only front or rear at 10+ yards and see! Wait, I guess that would make it an iron-only gun :-)
Closer in you don't necessarily
need an RDS or even irons to make decent hits if you have developed enough kinesthetic awareness through a solid,
consistent presentation ... but we don't have sights on our guns for those close shots, do we...