Only you can answer this questions, but I think you have heard some generalizations and over simplifications...
Battery life is not worse on Marshmallow, it is the same or slightly better... if you don't see that you should be prepared to clear your cache partition or factory reset. This is a major upgrade under the hood, although on the surface it doesn't look like it, you are moving up a full release (5 to 6) so lots of stuff is changing and TBH I recommend a full factory reset to keep things nice and clean.
As far as the touchscreen issues go, very few people see them just show up after going to Marshmallow, if you didn't have touchscreen issues on Lollipop at all, then you likely won't on Marshmallow. Marshmallow seems to exaggerate the touchscreen issues (phantom touches) that people had on Lollipop, few people had zero issues in Lollipop than suddenly issues in Marshmallow.
All that said, there are few real-life advantages of Marshmallow over Lollipop, especially since we don't get Doze mode on the Moto G 2015, but it always best to stay current for the most up to date security and bug fixes.