I don't see this as a beneficial change.
I play this game in ~2 hr chunks with my brothers. This change will hamper our ability to do TFs. If we don't finish in that 2 hour time frame (after recruiting for 15+ minutes). That TF is out 3 people, or if we can't get those people back we run the TF short 1-5 people.
My main on my old account had run all TFs except the shard TFs. Less than half the time we finished with all players.
Shard TFs were especially brutal, I tried one once. 2 people dropped because of time. There would be know way to complete that TF under these changes.
One other problem is the critters based on max level idea. If this stays, please add an option at the start to select a TF level between +1 and max level (if applicable), and lower the max number of people to 6.
As a casual player I had planned on getting my brothers to start some TFs by recruiting the minimum number of players needed to start and then running it with the 3 of us so we could experience this content.
If farming/soft loading is the issue here, maybe a rework of the TFs is the solution. Start with the "problem" TFs and then please go and rework the original TFs to be more fun and with less travel.
Sometimes the solution that requires more work is the right one.