A lot of good posts here! We should always remember that this is a freemium game, if we want or not, that's the thing. I'd guess most of us would prefer it would be different and a "real" game, but these modern times have modern solutions (to create money).
Nevertheless there are strategies to cope with the consequences the freemium approach has. I am only a bit sorry for the people that just have a "different thinking" - no offense, and sorry for bad english - and really feel the need to get everything as soon as possible no matter the costs. They might be the main goal of the freemium approach to milk money and this might also hurt people that do not have the money, but a high affinity to gambling. Today you don't need to go to the casino to gamble and lose money, mobile games do provide that, too. This is the main part of the freemium thing that I completely reject. There is a certain psychologic manipulation within many parts of the game to create the fear of the dark, eeh missing out, and to get people into spending money to be competitive, at least for a while. Good luck to everyone to find the right strategy for your way of playing!

About the Infernal Dungeon: it is NOT an event, it is a permanent addtiion to the game. Unlike the Trooper Dungeon there seems to be no difference in terms of costs, currency etc. coming. Correct me if I am wrong, please! So there is no need to hurry, especially as the rewards are rather lame I think, especially as the Reapers do not drop (or maybe with <0.5% chance). Sure, it is the guaranteed way to get the new Eddie, but is he that great? I don't think so. This means there is the great option to wait until you have the right characters and start the grind then. The only thing you should do within time are the class restriction runs in the hell & fire dungeon to get some free keys for the Infernal Dungeon. Apart from that I see no urgent needs at the moment.