Undersized parties - extended capabilities?

I love the undersized parties feature. However, the one thing I don't understand is why it's combined with unsynced feature. Could we have two different options in future?

Unsynced + undersized: Works exactly as it does now, letting you stomp old content for fun.
Synced + undersized: Simply allows you to enter old and current content with fewer than the maximum number of players. All other restrictions of synced content should remain. It might be fun if this mode allowed you to obtain rewards too purely for people who want extra challenge, but I don't mind there being no rewards at all.

I know on the surface this request seems strange because there is very little reason to want to wipe repeatedly on content without having enough people to clear it or even get to the final phases, however there are two reasons. It gives us a fun challenge, and lets small groups familiarise themselves with content before trying it out 'for real' in PF with strangers.

To give a specific example, I play with a group of friends and we like to try to do things together for the first time, but one of our big challenges in learning new content is that we can't actually go in and see the fights without studying videos online (not really fun) or embarrassing ourselves in PF inviting strangers to watch us fail. There are enough of us to make lots of mistakes while we're learning, but not enough of us to actually enter new content with eight people unless we recruit strangers. Furthermore, not everyone in my group speaks the same language and it's a burden to be translating between party members while I'm also playing my role in the fight. It would be great to have everyone fully confident with at least the first few phases of new fights before we start wasting other people's time.

In other words, it is much, much easier for us to come up with a basic strategy ourselves and then take what we learn into PF to finish the job once we know what we're doing. Some people do this using videos but the strategic elements are one of the biggest charms for my group and we'd hate to have to fall back on relying on the wisdom of others outside the game itself.

I don't really care if people think we're the worst players ever for doing this; it's our style and we're older players so we aren't ever going to be incredible at the game. But it's a shame that we can't practice new content without inviting strangers to make up the numbers at the moment. We don't expect (or even want) to clear content undersized and synced, we just want to practice, watch the cutscenes at our leisure and wipe millions of times figuring out new mechanics for ourselves in a relaxed environment among friends.

Could this feature be added, please? :)