I’m afraid you are missing the point here.
The issue isn’t about whether Telly and Vela are still usable or not (that is debatable and obviously subjective), the issue is that SG thinks it is ok to downgrade them again and again and then shift the blame towards players for not making changes in their teams.
If you go to a shop and buy a shiny phone with lots of features spending all your hard-earned cash and then a month later the shop owner comes to you and say “oh, we gave you a phone too good for the current market we’ll remove a few features’ I bet you would feel cheated and protest. Same here, players have spent money, time and hard-earned ascension items and emblems only to get cheated afterwards. For shoppers there are consumer rights associations that prevent this things to happen. Here there is only this forum and players should stick together to demand their rights to be respected with proper compensation.
And by the way offering proper compensation (not the joke they did) would allow SG to more freely experiment with new heroes to provide interesting variety, with the knowledge that should the screw up they could always downgrade the hero without backlash. Instead they created new HoTM a lot less interesting. Wrong solution to the problem.