Your example fits right in with an ongoing theme in WOT about misconception. Logain, of all the men out there, shouldn't use this comparison as he had already encountered Androl at this point and fought for him to be raised to Dedicated, or he soon would, based on his remarkable ability. We also know from Naeff (who Logain also knows) that a weaker Channeler with a strong affinity for a flow can match a stronger one, so Logain is even more off base with his assessment as Rand could just as easily be Gifted in Spirit and that would explain a greater effect with a single weave, or he could be both more Gifted and more Talented. No matter how you look at Logain's statement, it's stupid of him, despite being true as his rationale is not well developed since he took only one of the possible reasons Rands gateways were larger into account when there are quiet obviously many other variables that could account for it.

And you are ignoring a bevy of quotes/scenes to the contrary:

1. Siuan specifically states her Healing talent is the same as before. No less despite significantly less Strength
2. Egwene and Elayne are both poor Healers, by your reckoning they should be able to overcome this with more power. We've seen on a number of occasions that this is not the case
3. Androl can make a Gateway as large as Rand
4. Asmodean talks of how poor Semirhage is with Weather
5. Moghedien complaint about her lack of a stronger Talent for Compullsion
6. Naeff matching Nynaeve in Tear with flows of Air
7. Flinn notes he has trouble with gateways, indicating he should be able to make one large based on his strength

There are dozens more throughout the text ... Point being, you must FIRST possess enough Talent to be effective with the skill, only then will strength allow you to compensate and perhaps create as powerful an effect as a Channeler with a stronger Talent but less raw strength. And in single element weaves flow affinity will also play a part in the end effect or a weave.

All Logain's quote tells us is that Rand is both stronger and has at least a similar ability with gateways to Logain. By your statement Logain should also think Androl is stronger than he is!