I never really considered Assimilate as a meme archetype. As i've already said numerous times, its a fallacy to think there's only meta decks and meme decks, with no inbetween.
Assimilate is very different from other NG archetypes, as it barely has any control options, and it works similarly to other boost engine archetypes, like NR or MO thrive - on a long round, with multiple engines on board, you have Yrden or you're screwed.
So you probably already know this, but its best to bleed Assimilate. Sometimes even going one card down is OK, to ensure a small R3.
What i DO like about Assimilate is it's versatility. There are many variations, including some with almost 0 RNG: operator + diviner/ seditious aristocrats, these are crazy as you dont need to set up assimilate engines, and only after use create cards... you do both at the same time.
Also, there's variations with more or less spies, which synergize really well with assimilate (torturer is the perfect example, as its assimilate and gives spying)
And of course, there's the other point you mentioned, the risk of filling your board, why you should usually avoid long rounds vs assimilate if your deck already puts many units on board.
View attachment 11056973
And regarding mirror matches, this is what happens... note i didnt have enforcers in my deck, and my opponent no seditious aristocrats, and yet this happened...