Well, honestly, I did make some personalized adjustments to units stats when RS 2.6 was released. With chariots, I think the only thing I may have done is reduce the cost of the scythed chariots a little (but still very expensive) -- but maybe along with elephants they were also weakened slightly. Probably the Trocmi chariots are exactly the same as they were, although I wouldn't recruit those anyway. So, I don't think I did anything to change the situation dramatically, and what I said should be basically valid. But I rarely use any chariots, and yes indeed, I take your point, they are quite effective against cavalry in melee. I didn't mean to suggest they're only good as ranged units, or only good at fighting foot skirmishers.
The specific problem I was trying to address, however, is getting them into a melee with horse archers, which are faster and which tend to skirmish away from melee, unlike cataphracts which are inclined to charge toward anything and everything (not to mention that compared to chariots, all HAs have a longer range and more ammo, I think). If you can catch up with a HA and/or get it cornered somehow, then you should let your chariots have at it, because they'll rip the HA apart. But that's a big "if," especially when you're up against an army which has several elite horse archer units along with various other forces. And in cities, where you might think it would be easier to get HAs trapped somewhere, the chariots take up too much space to move around and attack effectively.
That's a serious problem. In a typical field battle, getting one or two cavalry (not six or ten or more) to move away from the pack and into the corner you've prepared for it doesn't generally work. If you're going to have your expensive scythed chariots attack a huge mass of HAs/miscellaneous cavalry, you could do so and they will probably do a decent amount of damage. But they will probably not make it out in very good shape, and you'd probably get better results and save money if you sent a larger group of less-expensive units to do things like that. The idea is that chariots can be the "muscle" for your HAs and coordinate their attacks with them, since chariots certainly can stand up in melee against cavalry, better than cheap/disposable units like tarantines (or whatever units you'd have to screen/defend your HAs from melee attackers, if not tarantines specifically). The chariots can make use of their ranged attacks along with the HAs (until they run out perhaps) while your real heavy melee cavalry are defending/attacking elsewhere.
Heh, sorry, cross-posted. I addressed some of that in the previous comment. With or without chariots, I usually send missile cavalry around the left flank (maybe one will hold back HAs close to my right flank, if I see there are lots of them in the enemy army). The general and cavalry follow behind them, also around the left flank, and a couple of archers stay behind my infantry line, firing at enemy ranged units that are most threatening to the infantry and/or cavalry forces. Slingers and skirmishers can screen the infantry, or holes in the line can open/close for them so they can fire in relative safety. So, it generally looks sort of like this at first:
HH
CC IIIIIII
---AA
But the melee cavalry don't have much to do at the beginning, just provide some insurance against charges from cataphracts/etc. that would otherwise think the HAs look like a tempting target. The HAs (and/or javelin cav) stay in front or closest to the nearest enemies, so they can make the most use of their ranged attack and protect the general from enemy fire. So the general/cavalry most often circle behind the HAs, and it winds up more like this:
CH
CH
---IIIIIII
AA
Chariots don't have the range that a horse archer does, but they can protect the HAs from other cavalry, by staying with them behind the *enemy* infantry lines (*edit*) while the cavalry go in for a charge. At least, like I said, until they run out of ammo. With formations like this, you can often get the enemy cavalry to separate somewhat from its infantry (while yours is still fairly tightly grouped together), so that everybody should be in the right place at the right time. But the chariots (or other fast multi-purpose units like tarantines) are generally either supporting a larger group of missile cav or melee cav, not going out on their own to assassinate a target or something like that.