X is a good trait. A has more of X than B does. Therefore A is better than B.
That is a non sequitur.
You can add, "All other things being equal" and it's still a non sequitur.
X being a good or desirable trait does not mean all things with more X are better. There being all sorts of reasons X is amazing does not mean X is amazing in all contexts and in relation to all problems.
You'd need to say X is universally good, and all other things are equal. In other words, you're saying the only difference between A and B is amount of something that is always good. With the premises that strong, then the claim works. However, it's now highly unrealistic.
It's hard to find things that are universally good to have more of. Any medicine or food will kill you if you overdose enough. Too much money would crush us all, or can get you mugged. An iPhone is amazing, but an iPhone that's found by a hostage taker who previously asked for everyone's phones can get you killed.
You can try claims like "more virtue is universally good". That is true enough, but that's because the word "virtue" is itself already context sensitive. It's also basically a tautology and immune to criticism, because whatever is good to do is what's virtuous to do. And it's controversial how to act virtuously or judge virtue. If you try to get specific like, "helping the needy is universally good," then you run into the problem that it's false. For example, if Obama spent too much time working in soup kitchens, that wouldn't leave him enough time to run the country well, so it'd turn out badly.
You could try "more error correction is a universal good thing" but that's false too. Some things are good enough, and more error correction would be an inefficient use of effort.
You might try to rescue things by saying, "X is good in some contexts, and this is one of those contexts." Then you'll need to give a fallible argument for that. That is an improvement on the original approach.
Now for the other premise, "all other things being equal." They never are. Life is complicated and there's almost always dozens of relevant factors. Even if they were equal, we wouldn't know it, because we can never observe all other things to check for their equality. We could guess they are equal, which would hold if we didn't miss anything. But the premise "all other things being equal, unless I think of some possible relevant factor" isn't so impressive. You might as well just say directly, "A is better than B, unless I'm mistaken."