I think that the pace off the game is currently off for several reasons:
Chloroplasts, mitochondria, chemoplasts and other endosymbiotic organelles are trivial to rush
I could write a detailed post about this, but suffice to say, the major eukaryotic organelles should NOT be purchaseable for a trifling 55 MP as soon as you get nuclei. The game should make it a random chance, heavily modified by environmental and ecological factors whether a species unlocks a new organelle at the end of a generation. Furthermore, unlocking said metabolic organelle (excluding mitochondria) should drastically decrease your chances of unlocking the other metabolic organelles (so possessing chloroplasts should massively decrease your chance of further obtaining chemoplasts as well). This would make your choice feel actually important and heavily determine your future playstyle.
But you shouldn’t be able to reliably beeline towards such a drastic evolutionary step, since it discourages any other tactics and cheapens an otherwise massive change in a phylum’s history.
There is almost no way to improve your cell apart from just spamming more and more organelles onto it
It isn’t possible to, say, gradually make your bacterium more and more resistant to extreme pressure and other environmental conditions, or to make it’s metabolosomes more energy-efficient, or develop the ability to utilize additional wavelengths for photosynthesis, or increase your cell’s perceptiveness to compounds in the environment, or develop new chemosynthetic pathways, etc.
This means that really the only ‘tactic’ that’s even possible is just adding more and more organelles. A logical outcome of this is that gameplay feels way too fast, since you’re going to rush getting new organelles to the detriment of everything else because there isn’t actually anything else to do.
The world is static
You start out in a world already populated by eukaryotes, with oxygen already at 21%, there are never any upsets to the environment, etc. Even though auto-evo is in the game, you are almost never actually able to see it for yourself since the world is already heavily populated and a random species getting an extra mitochondria is basically imperceptible. It would feel far better to start as the LUCA, with nothing but you in the entire world. To watch as new phyla diverge from yours, and then give rise to their own subgroups. To watch as photosynthesis first appears, and the atmosphere begins to change, introducing new challenges and ecological niches. To watch eukaryotes appear and diversify into their own little niches. To see the occasional drop or rise in temperature or another environmental condition cause mass die-offs. To have patches get separated, change, etc. due to to plate tectonics and the like. I know that something like this is planned for the next version, and I’m very excited for it.