Maiden comes after Helloween?! In your dreams maybe... Less consistent? The first 7 Maiden albums range from phenomenal to great - HW is not even in the same ballpark there - sorry. Of course, Maiden has never been melodic power metal to begin with - they are 'just' classic heavy metal and HW's biggest influence along with old Queensryche - whereas 'Ween is the epitome of melodic power/speed metal and probably the biggest source of inspiration for the likes of Stratovarius, HammerFall, Edguy, Angra, Rhapsody, Labyrinth, and Blind Guardian. All these bands have released some good stuff, even though A LOT of it is very similar musically, and Andre Matos is a terrible singer in comparision to powerhouse vocalists like Halford, Dickinson, Gillan or Tate.
I also think that Savatage (with Criss Oliva), Vicious Rumors (with Carl Albert), Crimson Glory (first 2 albums), Virgin Steele, Jag Panzer, Impellitteri, Riot, Leatherwolf etc. have released better, more original sounding music than the latest crop of bands you mention. Also, iffy (drum) production aside, but if you think of the new Crimson Glory as 'alternative' - you need help. This is heavy fuckin' metal, pure and simple. And to call Loudness cheesy - have you ever even listened to the album with Masaki from EZO and especially 'Disillusion' (which blew away Metallica's 'Kill 'Em All' at the time...)? I think 'chessy' is reserved for stuff like 'Pink Bubbles Go Ape' or Angra covering 'Wuthering Heights' - now there is an embarassment of major proportions. Oh yeah, Pegazus qualify as well - doesn't Oz have any decent metal bands anymore?