So that's the excuse for making the mode less unique? The reason I (I can't speak for others) was attracted to Taiko was because of how unique it was. By making drum rolls and spinners required objects you are essentially turning Taiko into a more mania like game and removing it from its roots completely. If you REALLY need to have them as required objects, the conditions to count them as a miss should be incredibly low to still reflect the roots of where the mode came from. Also just a thought, but it might help if the people designing the score system actually actively played the mode.While spinners and sliders are definitely required objects now, they are exactly what you said they should be. You have to hit a very small amount of the ticks at usual OD levels, and even at the highest, it's still less than half of the ticks, making the conditions to count them as a miss being rather low. Spinners were never a big issue and I'm more than certain many players were already completing or nearly completing the spinners to their entirety. This change does nearly nothing to spinners, other than importance.
Actually, my main concern is the fact that players new to Taiko might not be able to complete sliders accurately due to their nature of being similar to a mono-color stream. It seems like quite a step up from anything seen in a Kantan, Futsuu, or even Muzukashii for that matter. I understand that the percentage of required ticks reduce depending on the OD, but it still feels like it could be too intimidating for newcomers, and might isolate those who want to get into Taiko further. Spinners are fine, they require very few hits, and end as soon as all the hits are required, and even if you don't complete it, you're likely to get a 100 instead due to how quickly spinners can be completed. Though I will say, there is a sense of joy of getting points while hitting the spinner as opposed to only the end. A really simple fix to this is to award a small amount of points per hit, and then have the final hit be worth the most, like how again old Taiko has it, but still supporting the idea of ScoreV2 by not enough hits resulting in either a 100 or a miss. This would keep a sense of accomplishment to a spinner throughout rather than just the end of it, though this is a pretty minor point that I'm sure not everyone feels the same about.
There are a few solutions with the sliders I can think of right off the bat, all with their own benefits and downsides, though if the improvement of ScoreV2 continues the way that it has, it likely won't need any of this.
1. The easiest solution: just negate the possibility of sliders becoming a miss and instead have them contribute to or past the 1mil limit, similar to how old sliders were. The main downside to this of course is that beginners may neglect sliders too much, which can form bad habits, and it'd be reverting back to the old style of Taiko, though to some that might not be a bad thing. The benefit to this is that it would reward the more skilled players for fully hitting the sliders, whether it's to be able to hit that max score, or to even go beyond that max score.
2. Change the sliders to act similarly to how they work in original Taiko, but keep the percentage based sliders. This might seem odd, but if sliders could be introduced to players as "hit the drum as often as possible to clear the slider", it would be easier for newcomers to complete sliders. A few downsides to this is that it would kind of negate spinners to a certain extent, and points earned during the slider past the completion percentage might have to be awarded as bonus points, which might create a huge points inflation. Also, it would completely change how sliders had even acted before, which as we can tell from the osu! ScoreV2, people can go apeshit over this (for seemingly no reason?). However once again, this would reward skilled players for being able to rapidly hit the sliders compared to others, and could create new interesting mapping opportunities depending on who uses this to their benefit.
3. This has been added already to the minimal effect, but perhaps a slider hitting a repeat arrow could count as a tick mark, with how long the slider lasts being the exact same as how it is now. Currently you can make 1/3 tick mark sliders, which has pleased many people in the community, but why stop at 1/3 tick marks? Why not 1/1 or 1/2 tick marks for the beginners, or even 1/6 or 1/8 on the more difficult or point plentiful maps? Of course, the main disadvantage is if the beginners miss the tick marks on the 1/1 or 1/2 tick marks, there are less opportunities to save the slider, or if 1/6 or 1/8 sliders were used on beginner maps to try and give the player more opportunities, then the number of ticks required due to the percentage system would increase, which again makes it more difficult on the beginner players. However, with more tick mark options gives more creative opportunity to mappers, and more enjoyability can be delivered to players when used properly, as well as still rewarding the more skilled players for hitting all the tick marks in a slider.
These were just a few ideas, and none of them really have to be used of course. I can confidently say that I am looking forward to the future of ScoreV2 after the consistent listening to the ideas of the community rather than shutting them out. Thank you for the continuous work on osu! and ScoreV2.