From what's been reported, what I take from it is a sense of maturity and responsibility. If Miller thought it was in poor taste and timing to have a party during a losing streak, that sounds commendable to me.

As someone else asked, more details are needed for some of the other stuff. For example, did Miller always foot the bill himself and this year decided to change things up? That would look less favorable to him. On it's own, it doesn't seem unreasonable to me for Miller to ask everyone to chip in. But, did he preface the party with that or did he wait until afterward and then spring it on them? There's a big difference.