Here is (one of) the main reasons that there is some hatred towards this ride.
Ever since Deja Vu was removed, heck, when Psyclone was removed, the thought was that they would use that space for a station for the longest coaster on the planet, which they have been rumored to get basically since Maverick came out and the reviews were amazing. Rumors of using the old Metro tunnel have been going for at least ten years it seems, and with the removal of Log Jammer, by far the better of the two flumes as Jet Stream is pretty awful, the longest coaster, multi launch rumor began to pick up steam. Fast forward to about 2 weeks before the announcement and it goes from 2 miles, starting at old Log Jammer station, going back to Deja Vu, metro tunnel, basically what people were thinking would be the best coaster easily of the year, turned out to be what is Full Throttle and the space shot that is now open in the back corner.
With the amount of area they cleared, prep work was over 2 years, and then this comes along, disappointment will surely exist. At least for me, and I had gone there at least 10 times a year for a string of 8 years or so, I knew that this would never work at a park like this. The operations are just too awful to have this ride have any serviceable capacity. Combine that with the horrible announcement video of saying YOLO in it, and the "theme" it just was the perfect storm of awful. I'm fully prepared to admit I'm wrong and this will be extremely fun, but the backwards launch seems pointless, and with three trains of 12 riders (I think that's what it is, again I could be wrong) the capacity will be awful after the first month.
Take Tatsu for example, duel load station is rarely used anymore, and if it is, only two train operation, the third train has been stripped for parts, and most times I've gone in the past 4 years, it has been single train operation with waits over 3 hours. It's at the same park that during October has Riddler's Revenge, Batman, X2, and Tatsu all with single train operation, causing waits to get over 5 hours, and that's a yearly thing. So to pretend this won't suffer the same fate is just ignoring the past.
TL;DR: Didn't live up to the rumors, the theme is awful, the parks operations are horrendous, and they took up the last "prime" spot for this, with hopes of something bigger and better.
This isn't the first time the rumors proved to be false with this park, Kingda Ka was originally rumored to go to SFMM and break the 500 foot mark with the hill, budget concerns and the fear of downtime due to the heat, ultimately killed it (allegedly), and the next year Tatsu showed up, but that worked out pretty well. With Colossus rumored getting the next RMC iron horse treatment though, if this disappoints, it shouldn't last too long.