Throwers can be a pain too for that matter, but are more viable to catch, for me.
For reference, I'm an 18/24 build with 8 athletics, and it's not incredibly effective at running down kiters; I'd need to have 27 agi/9ath, likely, which would threaten my damage output/intake even more- or I'd have to wear my trusty Pelt Coat full time, which would make me even more susceptible to being one-shot than I am now, from all sources (even bumps if they're fast/heavy enough). Both groups were likely to have 8 athletics before this, but they also wore less by way of armor weight, generally. My total body armor weight was usually 6.1 without a helmet, 6.2-9.1 depending one which one I wore. I don't know if weapon weight even contributes towards mobility loss, but I use an Italian Sword, which weighs 1, an Elite Cavalry Shield which weighs 5.5 and a Red Tassel Spear which weighs 1.5 for a total weapon weight of 8.
Chasing a thrower like Chucky I'd have a moderate chance of catching him but it was still a toss up; I believe he'd rock a 12/24 build, though maybe 15/24- maybe he can fill us in. In any case, same agility/ath. I could drop the Red Tassel to lose some mass, and just hope he doesn't break my shield. One or two of those axes will kill me if they hit me. His armor weight's anywhere from very low (2 or 3ish total, maybe), to a bit higher, around Lamellar level. His weapon weight was typically 16 I'd imagine, from four stacks of those 44 cut base beast mode Heavy Throwing Axes.
Aderyn as an archer on the other hand, he'd wear much lighter armor all the time (white tunic, straw hat, some boots) and I could never catch him on my own unless he messed up or hit some wonky terrain. I believe he's also 18/24, though I could be wrong. I think adding more weight to the arrows is fair (though overdone, currently).
A thrower like Chucky gets only 12 shots, dealing more potential damage per shot, but he's paying 16 added weight and is carrying a weapon with physical length with affects to run speed. An archer gets many more shots at less potential damage per shot (though more total damage potential due to the number), but his bow has no physical length and he wasn't paying anywhere near the weight before. Now his weight from arrow/bow/blocking thingy combo seems too high. Assuming two stacks of bodkins, pickaxe/hammer, and Longbow it's something like 19-20 from arms and even more if he decides to use less damaging arrows at greater numbers.
It seems the weight is a bit extreme, again considering my melee/shield oriented arms weight of 8 for an infinite number of potential damage-causing hits (at an admittedly greater risk due to the proximity required to achieve them). The weight of arrows should definitely be toned down, but in conjunction with this, if it's possible, bows (and probably crossbows) should be given a physical length which affects runs speed like any other weapon. Bigger bows having more length. I lose speed from having my weapon unsheathed, all melee do, and throwers may as well (I'm not totally sure; maybe only in melee mode?) so why shouldn't it apply to these other things held in our hands?