So yeah, not as balance-breaking as having a third +1.3x boost to all Si/Gi/Ra techs for the classes with boosts in those techs. Giving a 90%-100% boost to one tech at a time is already giving FOs a good bit of power in areas where they excel, and a 60% boost for all Si techs for FOnewearl with Summit Moon and 60% Gi/Ra boost for FOnewm with Magical Piece and Psycho Wand (Gi techs for FOmar) is already large enough.
Most of the time when this discussion pops up, people want a 20% boost, equivalent to the color merges that almost nobody uses. The percentages above are already possible in this game with single-technique merges, just not for the whole family of techs. I, along with many others, am vehemently against a 30% boost. Swapping to single-technique merges is an integral part of good/optimized gameplay for a FO.
These merges will allow for "lazier" gameplay, in that you can now potentially stay on a merge for longer without needing to swap, but aside from the best players, nobody was really swapping merges to begin with. I cannot imagine anything drastically changing in the public/pickup games that the majority of players participate in.
Such merges would definitely shake up the TA meta for forces, sure, but it will not be "balance-breaking" like you describe. I can't think of any specific examples off the top of my head, but
at most we are talking about only a handful of frames saved per spawn.
Let's pretend that the merges will be a 20% boost. There will be occasions where:
- using barehand vs P-Wand is now possible, netting a few frames saved per cast (can't think of any spawns off the top of my head)
- using Ra/Gi merge is more advantageous for mixed-enemy spawns, potentially saving a few frames of merge-swapping, and also potentially saving 1 or 2 casts if the enemy's secondary/tertiary resistances work in your favor. Again, I'd need to note important mixed spawns and plug values into a spreadsheet to determine the exact frames/casts saved. I currently cannot think of any scenarios where you save more than 2 casts, though anyone is welcome to help me think of the edge cases
Here's where the actual controversy starts... those saved frames all add up, and will total to a non-negligible amount of time saved over the course of a run. Unfortunately, many old time attack records will become obsolete, especially those for one-person mode on a FO. This opens up a new can of worms altogether and leads back to the whole vanilla debate.
Although the time attack scene on this server is pretty dead to begin with, those holding records might be less than pleased if their times suddenly are under the threat of becoming obsolete. Since I don't have any records, I am not an authority to speak on this matter. I have only just begun my foray into the world of TA/optimization on FO's and have not been in the scene long enough to have any strong feelings on the subject. However, I will say that I personally find route-planning and theory-crafting
extremely fun and would love to incorporate these hypothetical merges into runs, but again, I don't have any records at stake. Also, if I were in the shoes of a record-holder, I'd hate to see my record erased by someone with sloppier gameplay, only beating my time due items that didn't exist when I performed my run.
TL;DR: These merges will not change gameplay very much. Certain spawns will become easier and faster, though the core gameplay element of actually swapping merges remains the same. Only the time attack meta will be significantly affected, while gameplay for the rest of the server will remain largely unchanged.