It's not about finishing early, it's about simplifying options to leave only the ones that are truly interesting. When designing anything, every additional element added also carries a cost, even if that cost is simply that the player has to remember it and account for it. Everything MC mentioned I believe was a good idea to cut; they simply didn't add enough to be worthwhile.
So you are proposing cutting Horse Archers and Knights? If you should I'm all with you. Otherwise I'm strongly against it. Very strongly.
I find it a hard time anyone has "reality issues" in a fantasy game... (and that seems one of the more commonly used arguments. Remember mechanics first, flavor second, balance third...

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If Horse Archers and knights are the problem (as in being to weak compared to chariots, which i would agree with), by all means improve them (they badly need it.).
If anything reduce the chariots' withdraw chance by 10%. Anything else would kill any! use for the mounted line except for the very few units (mostly horsemen) and a rare few civs (mostly the very aggressive ones/ Hippus and the nations/leaders with the defender trait...).
And that would be very sad indeed.
Because its one of the less interesting lines already (in fact it seems overall the weakest of the 3 regular military lines even with Chariots and War Chariots...
Edit: Archery is so far off in the back, it still shouldn't be even a contender hence me missing them. Still sorry for listing the wrong number.).
Would axing chariots make FFH2 a more fun game for the majority of players? I strongly doubt it (i doubt even many of the players in favor of the change really put much thought / experience into the consequences but sure i may be wrong and I'm strongly biased on the matter, I give you that.).
Its rather sad to hear Kael has issues with Chariots in the game. Both the AI and me seem utterly fine with them in terms of power / mechanics (the AI is! fond of withdrawl/flanking promotions for mounted units)... (and that while some dull civs like Doviello didn't got / won't get improved due to feature lock even if the verdict from the community both in terms of missing favor and most hate was beyond doubt, that doesn't seem to count for painful cuts.
So feature lock seems very relative...)
If Kael has heavy changes in mind (like cutting armored cavalry + stirups techs and moving horse archers / knights to trade / warhorses [which might make sense to a degree] i would like to hear about it before giving an opinion / verdict on the matter. But as it is with just cutting chariots announced i can't see a good side to it...)