Cartoon Network had crafted an enthralling story around Ben Tennyson from yhe original series through to the end of Ultimate Alien that grew with its audience. I was nine years old when the first series began and I found it enjoyable. If they didn't eventually have the more mature tone shift that Alien Force offered I wouldn't have been able to stay interested but they did. Ultimate Alien further expanded on this and it was building it into a very promising franchise. That is until the geniuses at Cartoon Network thought it would be a good idea to force a shift back to the childish tone of the OS. All that did was take any potential they had created for the series and relentlessly destroyed it. It seems as though we have Dwayne McDuffie to thank for what could have been something great and his colleagues to thank for ruining it after his untimely departure. Just when I thought things couldn't get worse they announced a reboot that starts things over with another 10 year old Ben which is a very obvious way of saying "yeah we ruined this series, we'd better just try again before we make it worse".
You are absolutely right about everything. I thought Ben 10 was one of the greatest animated series to ever been created, right on par with Avatar: The Last Airbender and Samurai Jack. It had an interesting premise, great characters, high quality animation, and a universe begging to be explored.
Then Alien Force was introduce and although it had some problems - Third Season was VERY mixed for me - I thought it was a good entry regardless. Plus, the Highbreed story arc was very interesting and I was waiting passionately for each episode on what was going to happen next.
Although it was trying to fix the retconns and plotholes introduce in AF, Ultimate Alien was another good entry as it had a solid first season and a decent one involving the Diagon arc, but the death of Dwayne McDuffie really hurt the production of Season 2, leading to a ridiculous amount of filler episodes.
I'm not going to bother talking about Omniverse, but the only good thing they introduce in that series was introduce Rook.
I'm going to give the reboot a chance as the reveal trailer looks promising...as look as they don't screw the character designs for Charmcaster, Hex, etc. Along with any other aliens.