Warning wall of text incoming - TL;DR: Add new mode to polearms & similar items that allow melee attacks from range.
How does having melee weapons with "reach" sound? Similar to the
with it's
one could have melee weapons and creatures with "melee" capabilities.
Each melee weapon could then have a "ranged" attack in addition to it's melee. A pitchfork for instance would be able to reach out one tile and also attack in melee normally. Halberds, Pikes, Spears could have a range of 2, while Whips and similar items could have a range of 3. Explosive-tipped lances (1concussive ammo attack, no battlescape reload)?
Utilizing spears on creatures to avoid reaction melees (I can finally utilize those pitchforks?) might be a thing. Having a wall of pikes brace against an incoming charging reaper (hopefully without the weird stealthy ai behaviour) would be pretty cool. Engaging Black Lotus with pitchforks sounds stupid so there is that, discounting throwing knives and guns of course. In addition, also discounting their poison-tipped Nakinata-wielders (wound stat +++). Deep One Spears would also benefit.
Weapons with reach will also dissuade you or the enemy from taking a step back and simply firing their guns if you give the ranged attack a "snap" mode.
Weapons with reach is obviously very powerful compared to those without, as history shows as well. In game I believe that the close 1-tile melee attack ought to be less accurate\powerful where there are reach attacks to create an "optimal" range. Get close to enemies with reach if you only have short-range melee weapons or stay at a distance if vice versa.
Now why all this? I think it adds a bit of extra flavor to melee, possibly making both strange creature missions more interesting as well as opening up a new dimension for melee combat. I don't know how feasible this is so if something can't be done or there is a good reasoning for why this can't or shouldn't be then I would not know about it.