If I continue on
Hookbill's thoughts on afterlife, if it was supposed to be something the Men fitted better to, then Melkor certainly did a very awful job to scare them of death. And also, I'd think that for example the Númenoreans who worshiped Melkor (convinced that Eru is a phantom - TP???) would be quite, you know,
perplexed after death. But these are just speculations, only random thoughts on that topic.
Which brings me to -
hewhoarisesinmight, you are actually saying, I believe, more or less the things that Sauron said to Ar-Pharazon. "His name is Melkor, the Giver of Freedom."
Gandalf would possibly call it "Repeating the lies I always heard only from the mouths of the emissaries of Barad-Dur."
I am not saying what you imply here is not true. But it is about
twisting (the world often associated with Melkor, Sauron etc.) the point of view: I think it is right to assume that the presence of Valar in ME wouldn't be good for Men, it is the same as if they were in Aman, as
Lal said. This was not their "cup of tea". This way, they could thank Melkor for this. But:
1) Don't forget that Melkor was Vala as well (Vala, is that what you said? Then your oath is sworn in vain!)
2) I highly doubt that the Men would have "peaceful life". We saw this at Númenor, and I think if Melkor ruled M-E, it would look similar. For example I highly doubt that most of the people there would like to participate on these human sacrifices (not mentioning that you always need someone to sacrifice).
3) As
Lal said, a lot of Knowledge and Art would be lost. Especially for the "elf-lovers" this would certainly be a bad time.
Lal, as you said about the hobbits, I'd like the same with for example walks in the forests under starlit skies, singing... but I am somehow afraid that part of the forests might have been burning and part of the stars will be clouded by black smoke from more Thangorodrim-like things. Mmm... also reminds me at the times of Ar-Adunakhor and further, the Elves ceased to come back to the shores of Númenor...
4) Worshiping Melkor for him getting rid of Valar is one thing, but this is the twisting I speak about
: we seem to be forgetting that the other Valar had their parts in shaping Arda, and more than Melkor (although he did as well). "And many here worked no less than you." And I consider it important to have in mind that if there was "freedom" (if they'd have any, see #2) for which they could thank Melkor, they'd have to thank the same way Ulmo for water, Manwë for clouds, Yavanna for fruit and trees and vegetables, and so on.
5) And, please, mainly: Whatever Melkor did for Men's "freedom", it was obviously unintentional. So I wouldn't even worship him for it. The Valar created the world intentionally and when they came down to Arda, they knew that they are preparing something for the Children of Ilúvatar. So for these, they'd deserve the praises, for they worked on something for someone else. But Melkor didn't want anything but to get rid of Valar. And had there been
So to sum it up: Yes, perhaps Melkor did a good thing to force Valar out of Middle-Earth. But if any man wanted to worship Melkor, who did this unintentionally, I'd call it fair that he also had to worship - even more - the Valar, who shaped it, and Eru, who gave him life, so Melkor would be on the 16th place at best 