There is another factor that warm water divers need to consider. If you are boat diving and/or getting in and out of the water many times during the day, it gets darn hot above water. The ability to get the suit off easily, especially the upper portions, is even more important that good fit. Not an issue if you get in and stay in, depends on your diving style.
I dive in about the same temp, boat dive so I get in and out a lot, and found that traditional freediving suits were to much hassle to get off. A 3/2 surfer suit, back zipper works fine in spring and fall. Riffe makes a two piece, 1 mil that is very good for summer(get the hooded version) and comes off reasonably easy.
If you are getting in and staying in, pay careful attention to other divers comments on warmth and exactly how they use their suits, water temp, depth, how long they stay in, etc. Small differences can make a lot of difference for you. If you really need warmth, there is no substitute for a good freediving suit that fits and is the correct thickness. My Elios is invaluable if the water is chilly.