First off, I’d like to say that there is no such thing as too many gods. The gods are the gods, they are as they are, and there are as many as there are. And I would never, ever say to someone that they worship, or honor, or recognize too many gods. That is wholly the business of them and their gods.
But that’s not to say that it can’t be problematic for us mortals to deal with a lot of gods. (So many gods, so little time. :))
But the ancients did it, so why can’t we?
Well, we can, of course. But many if not most of us are doing this on our own. We don’t live in cities where the many gods of our pantheon are honored by the many citizens of our city. Even in ancient times, each and every person in the community did not regularly and actively worship each and every deity recognized by that community. A household is not a city. An altar is not a temple–more specifically, a household altar is not a city temple.
What this means is that the ancients could do it because there were many hands to do the work. And, although there are not as many of us as there were of them, there are still enough so that we can each focus our own devotional practice to whatever extent we desire. We are still a part of a community.
Of course different folks will define community in different ways. Some people identify strongly with a particular form of practice or tradition and will consider only those who do likewise to be a part of their religious community. Others will feel that any who honor their gods are a part of the same community in some sense. (That’s my own opinion and bias, by the way–to me, the gods themselves are what bind us, and while specific religious practices or traditions may make up a community within a community, the greater community still acts together to honor the gods.)
I guess what I’m saying here is, don’t feel like you have to honor each and every deity in the pantheon (or pantheons :)) simply for the sake of “collecting them all.” If there is a god you feel should be worshipped, but you don’t personally have an affinity for, there is almost certainly someone out there who is already doing it. You can focus your own practice to whatever extent you feel is right, or appropriate, or necessary.
(I’m not saying not to worship any of the gods, of course, just that each and every god does not have to have a place in your daily practice.)
It’s all right to be focused on a few gods, or even on one god (a practice known as henotheism) if that is where you are drawn. The ancients had no problem with this–where they took issue was when someone would scorn or deny one of the gods in favor of another deity. Polytheism isn’t a popularity contest, and you can love one without disrespecting another.
On the other hand, if you do feel called to honor a great many gods in some way, that is also all right.
