Just going to say that I don't mind not having the sim option available instantly, but this was discussed when the event was still new (2nd or 3rd time around) on the CG forums.
Players need information on this stuff. Even if your plan is not to allow sims for the entire first year, just announce that. It may sound disappointing to some, but it's at least information that lets us know you're actively considering it.
You put a bunch of work in on these events, and you don't want that work to be irrelevant. You want the missions to get played multiple times to justify the hours put in on your end. That's fine.
And it's also fine to start out with a longer time frame than you need and then cut it back. You could, for example, start with something like, "We will allow these events to be summed someday. We don't know exactly when that change will be made, but current thinking is that qualifying for sims will be done separately for each UltJourney battle, and each one will require 3 stars on that battle plus 20 wins on that battle." And that gives you an insane amount of lead time to talk about this, and then if you come back after 12 months and say, "We've decided to introduce sims next month. The qualifying number of wins will only be 10, though those are counted separately for each battle and simming will still require having achieved 3 stars on that battle."
It matters that those of us who are busy have hope that the time investment for things like this will go down eventually. I won't say that video games are built on hope, but long-term investment strategy games like SWGOH can eat into other hobbies and activities. Let people know what you're thinking. Yes, there are people who will scream and complain if you change your mind, but use the Montgomery Scott principle and you will always keep your reputation as miracle workers no matter what galaxy you're in.
So please, if you're not planning on allowing UJ sims soon, just tell us so that we can make good decisions for ourselves.