I understand from one of the recent Kickstart updates that grappling in combat has been ruled outside of the scope of the P:E design and will not be implemented. The reasons identified are very valid and are similar to those identified previously in other (pseudo)turn based rpg games: the cost (time and money) of having separate animations for just one design feature (one for a creature in the grappled condition and one for its regular, ungrappled token), and conceptually handling grappling certain creature types (how did he grapple a ghost/mustard jelly/carrion crawler/etc). These are just two of the reasons that grappling hasn't been implemented previously in rpgs; I'm sure there are others.
However, as both a professional software developer (C#/java) and a practitioner of taijutsu (a martial art that places strong emphasis on locks and to a minor extent, grappling) I couldn't help but begin jotting down some notes and thinking about a very rudimentary, high level design for how I would implement grappling as a viable option in P:E. Obviously, I'm posting this in the hopes that grappling will again be reviewed for possible inclusion in the P:E design document. Here goes.
Assumption: both PCs and NPCs will have status' or conditions applied to them. Examples would include sleeping, sickened, prone, petrified, frightened, entangled, etc. These conditions will apply different modifiers to the creature's statistics, to include movement rate.
Design option: 'Grappled' now becomes an additional condition that can be applied to a creature by another creature, with its own associated modifiers to a creature's statistics. Specifically, I'd expect it would take a creature's movement rate to 0, and depending on the skill level or abilities of the grappler (i.e. a master monk) it could inflict a Damage Over Time effect on the grappled creature. There would have to be a mechanic developed whereby every round/turn a grappled creature and a grappler determine if there is a change in their grappled/grappler status. Similarly, 'Grappler' or 'Grappling' becomes another condition that would be applied to a creature that is succesfully grappling another creature.
Assumption: some of the above conditions (sleeping or prone, perhaps?) would entail displaying a separate animation for a creature that has that condition applied to them, a la Baldur's Gate and the Infinity Engine. Many creatures, while not being humanoid in form, will be immune to some of these conditions but others. A centaur, for example, could be put to sleep, but a ooze could not. This will require separate animations for some non humanoid creatures for certain conditions.
Design option: Some of these alternate animations could be utilized for a creature in the grappled condition. Perhaps 'entangled' or 'prone', or something similar. This design works for nonhumanoids as well as humanoids. The centaur was going to have a scenario where it was entangled or put to sleep, yes? Use the same solution for the grappled condition.
Design option #2: Just don't change the animation. A creature with the grappled condition has no change to its animation other than it doesn't go anywhere (movement rate set to 0). This one is easy peasy and wouldn't be too hard to swallow by the players either. Or put another way, it would be easier for players to swallow a system where they could grapple opponents, even if the grappled creature's animation didn't change, as opposed to no grappling system at all.
Assumption: there will be a priority applied to these conditions determining what animation is being displayed for that creature. For example, prone or sleeping has a higher priority than frightened for what animation is displayed, while a truly terrible condition ( petrified or disintegrated, possibly) trumps them all for displayed animation.
Design option: using the above design options, 'grappled' (and 'grappler' for that matter) simply becomes another condition with its own priority. A grappled creature has whatever animation is appropriate for that creature, but a grappled creature that is then killed from damage/put to sleep/disintegrated/what-have-you then assumes the animation of the (presumably) higher priority animation.
So why go to the additional trouble of including grappling at all? After all, even if the design solution for animations was to not include any separate grappled animations (the creature just stops moving), there is still resource cost in developing the grappling system design, coding it, testing it, etc. Can't we just skip it and live with the traditional monk punching/kicking for unarmed combat?
Sure you could..and then you'd be like every other run of the mill RPG that included unarmed combat (the truly bad ones don't even bother to make special allowances for it at all). Including some form of grappling combat in the system mechanics, regardless of the robustness (is that a word?) of how it's handled by the animation system, serves as yet another way that P:E is not only built upon the legacy of great isometric party-based RPGs, but is also raising the bar for them going forward.
That last part is sort of a lofty, feel-good, tickle-fights and kitten-whispers benefit. It's hard to qualify and impossible to quantify as far as hard benefit to the overall P:E design document and project plan. In more concrete terms, including grappling as a viable combat option lends itself to satisfying players that have been looking for exactly that (and in this age of televised Mixed Martial Arts fights there are more of them than you might imagine), and it opens up a fascinating new combat strategy (grappling) that has rarely (if ever) been explored before, especially in the context of an isometric party based RPG.
#tldr;
There doesn't have to be any additional animation cost to include grappling in the P:E design doc, and there are solid benefits to the game as a whole by creating a grappling system and making it available to the PCs as well as the NPCs.
