A thing to consider: in 4e, Con had a fairly small effect on your hit points. Your starting hit points were equal to your Constitution score (not bonus) + a fixed number depending on class (10-15, at least for the classes in the PHB), but after that Con didn't affect hit points anymore. Instead, Constitution's primary effect on toughness was its effect on the number of healing surges.1) Each class has 6 healing surges that fully refresh on a long rest (there's little reason to vary this in the way 4E did, and 4E had too many). Definitely do not add CON bonus to this number.
I think that would be a fundamental math alteration that would be unhelpful, esp. as it would impact monsters, so I'd avoid that. In 4E it just felt like it boosted the number of HSes from "I might hit the limit on a very bad day" to "I will definitely never hit the limit", so I don't think it had much real value either way. I think in several years of 4E I saw someone run out of HSes exactly once, and that was in a truly crazy situation the party could easily have rested earlier in.Having Con have a strong effect both on hit points and healing surges would be double-dipping and probably not good. But I could easily see a variant that got rid of Con bonus/level hp and had Con add to healing surges instead.
It generally hasn't impacted it that much for me. My players tend to choose racing the enemy down rather then backing up and healing a lot of times. But if they are in a defensive position, like behind cover, they can rally more. So it tends to keep them a bit more mobile and looking for places to safely hide out - like behind a wall - to force the enemy to move closer to close around. This can get used a lot when there are large fights and reinforcements are coming. They can healing surge to get ready for wave 2.Hm. I guess Healing Surges are about as popular as I had feared. ~sigh
If you're one of the two people who are still using this variant, I'd like to hear from you. I'm interested to know how it has impacted your game.
Perhaps. I am kind of fond of Genesys'/Star Wars' stat spread: Brawn, Agility, Intellect, Cunning, Willpower, Presence. Brawn incorporates pretty much anything that has to do with both Strength and Constitution, and Cunning, Willpower, and Presence combined fill in the stuff that's mostly covered by Wis and Cha in D&D. For example, Coerce is Will, Deceit is Cunning, and Charm is Presence.I mean, if there's one stat in D&D that could stand to be deleted though, it's CON - it doesn't impact any skills, isn't a primary attribute for any class, and basically only exists for the purposes of saving throws/concentration checks, and boosting your HP into the sky, both of which could be handled differently and likely with a superior overall outcome, but that's a whole other separate thread which I think we've had before.
To quote a great film: "Perfect. Then that's the way it shall be."In 4E it just felt like it boosted the number of HSes from "I might hit the limit on a very bad day" to "I will definitely never hit the limit", so I don't think it had much real value either way. I think in several years of 4E I saw someone run out of HSes exactly once, and that was in a truly crazy situation the party could easily have rested earlier in.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.