there are 3 things that might happen when back-pedaling due to the poor way some stuff was implemented in Mount and Blade(not the mod's fault, it's a flaw in the game code):
When u hit a troop and he get's the mini-stun effect, another troop unit will run through him as if he were a ghost, most of the time this happens u get a free hit from the glitchy thing, it's the most usual way of dying when doing that...
Sometimes arrows and some high reach weapons will go through enemy units and hit u, that's another way of failing that tactic.
Sometimes the AI(VI as they call it here) will zerg you in a way u get surrounded, even tho they don't have range to actually hit u, the above glitches apply and u die almost as if from an heart-attack.
Sometimes, when in a minor fight, they AI/VI surrounds you and stun-locks you forever. (Only a few mods allow u to not get stun-locked by having increased armor resistance factor in their modules, the ideal approach to that is making mid-low to low tier weapons to have zero effect when hitting someone heavily armored, and, avoiding stun-locks and knockdowns from better weapons while still receiving dmg, since each mod does this differently and I am new to PoP, idk if there are any armors that can have this effect here)*
PS: If you get an badass armor like that in a mod that balances these stuns and knockdowns you can actually tank enemy units for quite a long time, the recommended weapons for this kind of tanking in M&B are low reach with fast attack speed, of course one can have slow attack speed maces once they get past 300 of one-handed proficiency.
On sieges or other crowded situations you'll find that 2 handed weapons are almost useless unless they have 80 or less reach, even tho the shorter the better in these situations, knives never apply to these rules since they have really low damage. Maces are still the best option due to Blunt/Puncture damages, which are effective against heavy armor.
EDIT: In sieges I change my weapons depending on the layout(usually I besiege and save, go into the siege and take a look, leave and reload so I can be prepared). Some times it's good to bring ranged weapons like crossbows and bows(thrown weapons are almost useless since they have too low ammo and awful aiming and range), if the siege scene is very small and gets too crowded I bring one high range weapons(either Polearm or Two-handed) one shield and one low range weapon. Whenever I get stuck I use the low range weapon, when I'm behind troops I use the long range weapons... I do recommend ranged like Xbow and Bow only in sieges that have plenty of empty spaces and long distances between you and the enemy units, or, when u are using the arrow rain tactic...
There you go, my best tips
* - In my experience the best mod in that regard is 1257 ad, it makes really hard to take down armored units in early game, but I find it the most fun in all mods, if it's realistic or not, that's hard to tell, I've never being hit wearing some armor, so I don't really know
