IMO the maceman promo to CR rifles is a bit of a niche thing used when you're desperately small and need to focus total empire output on leveraging a military advantage at all costs (exception: aforementioned berserkers).
A lot of people like the CR on rifles, but there's a couple reasons I'm not sold on it:
1. Obviously, if you're relying more on the draft most of your units aren't going to have it.
2. Once defenses are down, rifles have pretty good odds against anything that defends, with the exception of high CG muskets (and same-era things like other rifles or grenadiers with CG or on counterattack).
3. People kind of assume no CR in this era, but it's not entirely true. If you instead go for steel first, you get all the CR you want without upgrades. Anything can finish off units red-lined by cannons, and just some pikes/muskets are all you need to cover them...techs you'll have.
That said, upgrading a bunch of troops may be your only means to come up with enough

quickly enough to actually be fighting longbows rather than rifles on high difficulties, and that trumps any upgrade inefficiency. Nevertheless, even if you burn a merchant this is harder on tech rate than conventional means and even more so than drafting, so use with caution.