Well, first off what is quite a bit of resistance? Depending on the person, any amount of resistance may be too much. I have a Morgan large chamber #7 jazz alto MP and it has a little resistance as well. I use a 2.5 strength reed with it. You don't specify what your tip opening or what reed you use either. If you use a hard reed you will likely experience more resistance. I also have a Wanne Gaia #7 that is extremely free blowing with no resistance whatsoever, which sometimes will cause my sound to be thin in the upper register. My main MP these days is a Brilhart Tonalin #5. I wouldn't say it has any resistance but neither is it free blowing like the Gaia. For ME it's the best MP I've ever played on.
To me resistance within this context means a feeling of having to blow harder to get the reed vibrating effectively. Perhaps I can describe the feeling as being the opposite of free blowing. "Quite a bit" is in reference to other alto mouthpieces that I've played (a small sample size to be sure), on the same instrument, again purely my subjective experience.
The mouthpiece tip of my Morgan classical is an 8, not far off from some of the other mouthpieces that I have, and recognizing that the facing curves likely differ between them.
Your point about too hard a reed is a good one relative to the feel of resistance; I used 2s, then 1.5 and went down to a 1 (as low as I could get), and still felt more resistance compared to my other mouthpieces (that I find more free-blowing).
As you point out, it is a subjective feeling and I meant to qualify my experience specifically with a mouthpiece described as:
Large round chamber (no baffle)
Rich, dark classical tone
agreeing with and in reference to the prior post, "It's the attributes that help facilitate sound. Flat or rollover baffle and large chamber will help produce a darker sound."
In no way do I mean to criticize the Morgan classical nor dissuade anyone from it or any other large chamber and small or no baffle mouthpiece.