It is damned time we see a great version of Brainiac. The character is Superman's number 2 nemesis and we've never had a decent live on screen version.
As for Luthor, the last few decades (both on screen in Smallville and in the comics) have shown the character works best as a foil for Superman rather than an outright villain. The last attempt to make him a full villain during the lead up to Death Metal was contrived and came out of left field in the comics continuity. (I blame editorial for that.) Luthor works great as a character who is driven by his own ego and his own motivations and desires, but who is not an outright villain. To me, he is a member of Clark/Kal's supporting cast. On screen, I would love to see Houlton return as Lex in that capacity.
This?