I really prefer ppv2 over ppv1 from what I've seen because it actually feels valid to say that if you have a marginally higher PP than the opposing player you are probably more skilled, rather than just saying someone played more or grinded more ranks.
From all the replays and everything I've seen in top players this is what I think needs to be buffed/nerfed/changed. I'm not a very good player or anything but I guess I still have an opinion
1. Length (in hit objects) need to have more of a value. Players with high stamina in maps should be rewarded more, with some of the hard long maps/marathons actually being pp farmable. If you look at the best scores in osu!tp top 50 scores, there are 11 TV Size DT Scores (13 if you count Killer Song), that seriously popped out of nowhere, and didn't seem to be as hard (didn't take as much retries or effort, from what I've seen in spectating) as some of the longer maps like Freedom Dive or Bikko's HDHR of Mago De Oz.
I decided to think of a couple marathons that would be fucking sick to DT, and what came to my mind was:
https://osu.ppy.sh/s/108296 This map is a 12 min long marathon that is p popular now, and was the map I personally used to practice AR9.
With that, I used osu!tp to estimate the amount of PP a HD,DT play of this map would be worth (with acc around the lower 99%, because its simply more convinient) and (although I know DT recalculates speed and aim difficulty) DT tends to buff the aim and speed values by about x3, and HD gives a 18% bonus to aim, DT/HD gives a x2.05 buff to Acc from raw estimate, this gives God Only Knows DT a surprisingly low tp value of 379 estimate (probably off, but aroudn that area)
That is less than a DT HD Play of this map:
https://osu.ppy.sh/b/408128 -- a one and a half minute song which gave sayo 435tp after doing it. The stamina required to do all the jumps and rather high BPM streams (specifically at the mars part) seems to be more than the DT sayo did on the previously mentioned map.
The only problems I see are maps like The Unforgiving being worth a jesus load of pp lol.
Well I guess i'll just drop some maps that in my opinion wouldn't be as undervalued if length were to be given a bulk
https://osu.ppy.sh/s/25403 - Various Artists - osu! Stream Compilation
https://osu.ppy.sh/b/343741 - Hanatan, yuikonnu & Mitani Nana - Songs Compilation [Rabbit Face]
Every DragonForce map
https://osu.ppy.sh/b/252238 - Tatsh - IMAGE -MATERIAL- <Version 0>
ok wall of text 1 is complete, ill try to make no.2 a bit shorter
2. Single Tap maps high BPM whatever
Although Scarlet Rose isn't the hardest map, I have no idea why WWW's HD/HR FC with only 6 100s is rated so low, not even worth 300tp on osu!tp, on a map that where the top 50 aren't even all FCs, or why With a Dance Number gives so little pp. It was mentioned previously in this thread that it should be buffed somehow, but really, val0108's maps really need to be worth more.
I did a similar test to the God Only Knows play, but this time looked at a play that has already been done
https://osu.ppy.sh/b/99094 - Megpoid GUMI - Carnival
Cookiezi HD,DT'd this map (I have no fucking clue how, but he did) Comparing the score on osu!tp of the player, furikake on carnival, which has a similar accuracy to what cookiezi got on the map, and applying the DT estimates of x3 Aim,x3 speed and x2 acc, carnival would be worth an estimate of 353tp. For one of the hardest DTs Cookiezi ever did, that is really little, in comparison to a DT like everyone doing Magic Girl!!, which is worth more tp than Carnival, as Magic girl is more focused on DT Jumps than single tapping like jesus. (mentioning this map because it has a similar length) fast singles definitely need a buff.
3. Just a quick note, FL needs to be buffed on longer maps, as being able to memorize a longer map is much harder than a short map. It's easier to remember a short song with jumps than Flashlight on a marathon.