Technically both, but having them without any trade off is by far the worst part!
Look, with my suggestion of a Control Ward Trinket, everybody could use that and would have exactly what I described. Potentionally 10 wards placed and even 10 wards to replace, while everybody is full build.
But with the tradeoff that mid and adc dont have the safety of the bluetrinket, the jungle/assassins lose access to the large area clear+invisibilty against wards. Only support and toplane woule be the ones that could prefer a Control Ward Trinket, at least in lategame.
So we would never see a 5 Control Ward Trinket team, because the trade of would be to high.
Obviously as long as the lategame isnt reached, everybody should have a spot to take a Control Ward.
Another problem regarding the lategame is the permanent duration/vision and how hard it is to kill them.
Think about a siege situation at your inhib towers.
With 5 Controlwards it should not be possible for the defending team to get vision of the attackers (because their wards will be cleared) and they cannot flank because the jungle would be permanently lit up.
Those Control Wards give just to much power in terms of safety and vision denial and ontop it favors the winning team, because they will have their Wards standing because they can defend them. They could trap enemys if they want to clear the wards(because they have no vision) and they also, because their wards will survive, have access to relocate/recharge them, thus can clear any vision in any area they like.
Normally you would have 1-2 Control wards in key areas, and the rest is lit up by non permanent, more easy to clear, not enemy vision denying normal wards. Aka it is possible to have some vision, to move around and potentionally flank the enemy. That is not possible/extremely hard if we replace them with Control Wards!
Since it could be that we get 5 people running around with a Control Ward trinket, I suggest that the recharging only starts when the Control Ward gets destroyed (but with a little bit reduced recharge time, compared to the "current" version). But this is very unlikely. And I would only do that if things get out of hand.
Like I said Control Wards grant more power then you might think, thats why, if we grant players access to them, there must be a trade off!