One stat to rule them all, or what if we merged Dex and Str?

[diplomancer]

No, but they have a space for "Strength" and the rules for how much you can carry are in the PHB, and are based on STrength. Merge Str and Dex and now you have anybody who is agile being able to carry a lot of weight.

If that's the main problem that this rule would bring, I don't think it's a big deal. It's definitely not more of a big deal than small characters having the same carrying capacity as medium characters, or, for that matter, most small races not having a Str cap. Personally I think it's just weird to accept one but draw a line at the other.