Swords in different directions: Possibly something to be done. I guess that depiction is used because "/" is generic 'weapon' in DF.
If taken with a more Nethack spin, originally, "/”-placed items would have been wands, with items likely to be posed in 'graphics' format to best befit their ")" and "(" origins for (classic) weapons and tools respectively. The pickaxe here being a debatable either/or, though demonstrating one posdible reason for consistency, making the "\"-orientated pick stand out as a special case at a quick glance.
Ranseur: Maybe. Later I mentioned the 'tridential' (trident-like, i.e.) spear. This is probably what I was refering to, but neither that name nor that of the related Partisan look like the name I still fail to remember (and it also isn't the Sai dagger). As for this maybe-crossguard being too large.. it's on the very edge of useful pixilation without looking like a plain line. With the slight curved extremities it could even be a fully rounded thing ("bell-guard"-like, as in épées and foils, but shallower and inverted - making it look more like a wooden-bladed, metal-gripped training 'sword' in reverse) or because of the diagonal jaggardness forced upon it by pixelation have the qualities (also mentioned) of ice-axe blades with vicious serations (could be a 'can-opener' design, used to trouble an armoured foe (natural scales/etc or manufactured stuff) by piercing straight into any plate it can pierce and then with a levering action each way do significant additional damage to the armour, and not do much good to its inhabitant either as the tip waggles, and potentially 'whisks', around in the squishy interior).
Not that I think any of these depictions are 'wrong'. Fantasy weaponry often comes in far more
fantastically impractical forms that defy pretty much all logic, so excuse me if I barely twitch reality as I voice my own
head-canon. In the world of DF, it's not inconceivable that this is an offshoot from a slightly different original set of farm-tools where a different kind of bale-spiking tool was used than our very own multi-tined pitchforks/etc, and from that arose the crossbarred-spear we (perhaps) see before us. Very feasible, even if still entirely incorrect.