Lal, having just seen it myself, I can easily understand why someone would feel this way about this movie. Some aspects of the script could have used more work.
I quite liked it on the whole though. Terminator movies have never been Shakespearian-level dramas, absolutely not even the first one, despite its comparatively much tighter, smoother-running script, so if you just disengage brain before starting to watch it, you should be able to enjoy it just as a summer blockbuster movie where tons of shit blows up. At least there's no Shia TheBeef running around looking like a complete eejit all the time, that's always something, right?!
Before I saw the movie, I read the header of a review pretty much slagging it like you do, with the addition that Arnold was the movie's saving grace. While I did enjoy Arnold's role, it was Miss Clarke as Sarah Connor who saved the movie for me. She was really great; great intensity, great authority, mixed with some of that fanatical edge the character had acquired in T2. A worthy successor to Linda Hamilton, I thought, and one of the best action heroines we've seen on the big screen in absolutely years and years. She looks younger than Linda did in the original Terminator though methinks, but that can't be if she was born in '82... *shrug*
Kind of missed that poor psychologist, Silberman or whatsisname, from the first movie though, but maybe they thought that would have been stretching the running gag a bit too thin...
(Or maybe the actor simply retired, or died, heh. Rise of the Machines was a while ago now and he was oold even back then.)
Plotwise, Genisys was...confused. Heh. I didn't really enjoy the badguy; making the terminators so powerful forces scriptwriters to have to write increasingly more implausible endings, but all the nods to the original movie felt great I thought. The grizzled cop character, even though we don't really know who he is, was a nice touch.
It's a quite watchable 7/10 on my scale, if you just send your brain off on vacation as mentioned, and it probably won't stand up to the test of time like Cameron's movies, but it's decent enough on its own.
Not sure it's suited for an 8-year-old though, because even with fairly little blood and gore this time around and not too many apocalyptic shots of piles of human skulls being crushed by murder machines shooting up droves of humans, it's still pretty grim. Why not take the little rugrat to a Spongebob screening or something like that instead?