Aside from various reasons already brought up, another reason why the Cruiserweight Championship being reactivated would be redundant is that it sends the wrong sort of message. When it comes to restricting wrestlers via weight classes, most American fans simply aren't huge fans of it and it's never been widely popular. For instance, the NWA World Junior Heavyweight Championship has been in existence since 1945, yet how many holders of the title have become widely known names among American fans? Limiting wrestlers via weight restrictions sends a message to a lot of fans, unintentionally in most cases, that these "little guys" simply can't hang with "big guys" and are therefore inferior. Is it true? Of course not, but it's certainly a perception that's created and perception is very often perceived as reality.
On the WWE's main roster, pretty close to half the wrestlers could qualify to be "Cruiserweights" as many of them weigh less, right at or just slightly more than 225-230 pounds. Even in NXT, a lot of them could be "Cruiserweights" as well. The main event from NXT Takeover II featured a fourway match in which the heaviest of the wrestlers, namely Tyler Breeze, was billed at only 205 pounds. Kenta Kobayashi, now known as Hideo Itami, has been hyped as one of the biggest international stars and signings in history and he weighs all of about 185 pounds, yet he sent both members of The Ascension, one of whom is billed at about 270 pounds. When you consider the sort of success we've seen "little guys" accomplish in WWE, it just doesn't make sense to limit them based on how much they weigh.
I agree with the opinion that WWE needs to get its current mid-card titles to a better place before even considering adding another one to the roster. I ultimately get the feeling that Miz, Ziggler and Sheamus have been placeholders for the titles they've carried or currently carry until WWE feels that certain wrestlers are positioned to take them. My opinion, and that's all it is, is that Wyatt & Rusev should be the next IC & US champ as Wyatt is rumored to be up next to feud with Ziggler and it just makes logical sense that Rusev, the "hero of the Russian Federation" gains even more heat by being the first big, bad, "Russian" heel to win the United States Championship in nearly 30 years.
At some point, maybe sometime next year, I can see WWE unifying the IC & US titles and if they want to create another mid-card title, possibly for more of the lower mid-card guys, I think they should just go the route of reactivating the WCW World Television Championship and renaming it the WWE Television Championship, or create a new TV title altogether.