I'm currently in the midst of a playthrough with this mod and have had 3/4 of the Fallen Empires in my galaxy declare war on me for reaching Alpha technology. While I have been able to come out on top in each of these, a few circumstances have made fighting them quite frustrating.

The biggest problem was reaching FE systems. AI empires seem to be unable to close their borders to FEs, meaning they can easily reach my systems but I am forced to route my fleets around empires that have closed their borders to me. In 2 of these wars I was entirely unable to reach the FE's territory because they were enclosed by rival AI empires, meaning the ONLY way I could attack them was to declare wars on other empires that I otherwise had no interest in starting.

The solution I would suggest is a new unity ambition that forces empires to open their borders to you. It could last 5-10 years and come with opinion and ship upkeep penalties for disrespecting sovereign rights and operating far from friendly starports.

The other thing that bothered me was the Xenophile FE that declared war on me. For the majority of the game, their opinion of me was Patronizing and they even gave me the Precursor Database, but now after watching me defend myself from 2 others FEs, they suddenly don't want me to have this power? It's a little bit disappointing to see my work in maintaining good relations with a FE to suddenly and irreparably collapse without any ability to prevent it.

Anyways that's just my two cents. I've been really enjoying this mod across several playthroughs despite my annoyance at these recent events, so thanks a whole lot for making the game a lot more interesting!