Spellogue started this question some time ago and there were no replies, but since I've run into the same question, I thought I'd reopen the topic.
I also make my cheeses from goat's milk that is inherently mild-flavored. The advantage I see in that is the ability to make cheeses that are normally made with cow's or sheep's milk without the result being overly 'goaty' in flavor. However, if I make feta, for instance, without lipase added, there is virtually no feta flavor--and I've tried 'feta' type starters as well as MM100, without any increase in feta flavor. I only get the feta flavor if I add lipase, and it doesn't seem to matter whether I use lamb or kid, although there may be some difference in strength of flavor. The only time I had reduced flavor (about half normal) was when I tried the 'sheep lipase' from a supplier that repackages, so I don't know the origin of that particular lipase. I had to increase the amount by nearly double to get the same 'strength' of flavor as with that from other suppliers. There's a lesson there (certainly on 'cheaping out and whether it really is cheaper') and I prefer now to purchase only in original packaging, or from a supplier in whom I have utmost confidence as to quality.
I also made feta from standard, grocery store cow's milk before I had goats, and made very acceptable feta using either kid or lamb lipase. While my manchego and other cheeses that are normally sheep's milk cheeses are not exactly the same as the 'real' thing, I don't feel the need to limit myself to traditional goat's milk cheeses. Whatever they are, they are mine and if good to eat, high quality overall and enjoyable to make, that's what I'm aiming for. After all, how many people use water buffalo milk to make mozzarella?
Perhaps others have had a different experience and can chime in. One of my current challenges is to get MORE 'goaty' flavor into my cheese when I want it, without resorting to lipase--such as in trying to duplicate the flavor of Beemster Goat Gouda--which may be the same as Cypress Grove's Midnight Moon. There was a thread on how to duplicate that cheese some time ago and it went in the direction of specific NSLAB's/adjuncts, as I recall, with Pav providing clues/guesses. So I've been concentrating on the cultures and adjuncts approach, in this case, as opposed to lipases. And soon, also, testing some of Yoav's (ArtisanGeek) specialty rennets, to see if there is a flavor change effect. Interestingly, lactones (which contribute to flavor) are not enzymatically formed in Gouda (Alewijn et al, attached).
In Improving the Flavour of Cheese (not that I have that book, but hope to get it at some point from my UC library) there is an excerpt on the addition of lipases to make certain cheeses.