What's done is done with this movie and I think the saving grace is the design choice they went with for the Upgrade. It's not out of the realm of possibility for them to get as large as Upgrade. Any bigger though and we will be treading in some awful storytelling and design territory. A few shots do look a little too CGI (like when he's roaring) but, as a whole, it seems acceptable for the species mythos.
I also hope this movie is a complete success but I'm ok with the series going into hibernation for a bit before another sequel emerges. Personally, I like that each sequel, so far, has been more standalone rather than direct sequels. Little call backs to previous films is ok but I don't care to see an all out Independence Day-Predator series unfold after this one.
Of course any Predator movie should revolve around the hunt but I think a big thing that helps keep these types of stories fresh is the different settings. It would be cool to see a Predator movie set in the old west (or another time period), but I get how that is something big studios are not looking to put money towards. I think the upgrade/bad blood concept is a fresh and viable route to take sequel films however. Perhaps take a story back on another hunting planet or, dare I say, their home world. Execution is everything but it's easy to see how that could completely ruin the image of the creature and the series for good too.
Heres hoping the video game industry puts out a new Predator game or two that is willing to unveil the species in certain ways that probably wouldn't work in movie format. Frankly, I'd rather see a detailed Predator games than unoriginal sequels pushed out by a film studio.