This is very interesting. I just put 1118 in the beginners category, and was going to give it a back shelf status. Due to the fact that it is in most kits for it's aggressive/reliable ferments ( meaning it is a kit fail safe), and many comments on this board about people moving past it, suggesting that most start there, but it leaves room to grow understanding and skill. Also the lack of depth it can give, where other yeasts will develop more character specific to the varietal, 1118 is said to not have those character/nuance building attributes.
Then you read an article on glycerol, something I have not yet considered in wine making, and learn that 1118 is a high producer. Yet, the whole reason for your post is that it produced a wine lacking body in comparison to a yeast with not much higher production characteristics.
Sometimes this hobby can be a bit of a mind #^@% and I am just left staring at the ceiling fan in contemplation. ( NO, I wasn't just doing it as I was trying to express my thoughts!)
Reading the earlier posts my initial thought was these guys are missing the point. I don't want to add glycerin, I want to learn how to make wine without needing a 'cheat' to get what I am aiming for. That is what Dave is trying to understand. I am not holding firm to that thought after more understanding of the make up of wine and it's natural production in fermentation, but I still NEED to do the experiments before just adjusting at the end.. Having already read of people making wine A with one yeast, and wine B with another to blend for different characteristics, this would be my first area of exploration.
Thinking about it, you have already done it, just not with the intention of blending. I would be very interested to see how a blend of the 2 above wines would compare to them individually. I just tried it with 2 wines with different acidity levels. One I thought was a bit high and the other slightly lacking. Together they made a mess of the subtleties of both and the test gave me abetter appreciation of them both, so I didn't blend, but I am glad I tried.