I tried looking but failed to see any other discussion of the big grasses following the second moves update with Gen 2. So, I did my own attempt. Basically, I wanted to see how the new grass fit and how a bullet seed exeggutor compared. I consider both legacy and non-legacy movesets for venusaur, vileplume, bellossom, victreebel, exeggutor, tangela, and meganium (considering only double grass sets). I believe this is all of them. For tangela, grass knot (GK) and power whip are considered identical. Solar Beam is abbreviated SoB and Seed Bomb is SeB.
For defensive scoring, I just took the product of stamina and defense and divided by 1000 to make them reasonable. This is based on the damage formula, where HP lost is inversely proportional to defense. These are listed below.
Mega - 32.32
Venu - 31.68
Exeg - 30.00
Bell - 28.35
Tang - 26.65
Vile - 25.50
Vict - 22.08
Next I considered the offensive output of each moveset, taking in to account STAB and the attack stat of each Pokémon, assuming 100 defense. This is 1.25attack/defensecycle dps. Cycle dps was found first for spamming quick moves without dodging and then using the charge move. It was next considered with dodging, so as many attacks as possible in under 1.5 seconds. This is just one razor leaf and bullet seed per window. However you can use vine whip twice. It was assumed in dps calcs that using your quick move(s) then dodging took an average of 2 seconds. As an example, for vine whip and solar beam, it takes 17 vine whips to charge the bar. This requires 9 windows for quick moves, so you could really use vine whip 18 times. Next window would get solar beam.
Dps = (187+180) / (92+4.9) = 13.4 dps
Once I had the cycle dps and associated offensive score for both cases, I averaged them and used this to rank. Below is the list, with each associated damage scores given, in rank order. There are 18 entries.
Exeg - BS/SoB - 55.05, 36.70
Venu - VW/SoB - 49.01, 33.17
Exeg - BS/SeB - 45.98, 31.71
Vict - RL/LB - 47.87, 28.98
Vict - RL/SoB - 48.65, 27.69
Tang - VW/SoB - 45.29, 30.65
Tang - VW/GK - 44.61, 31.11
Vile - RL/SoB - 47.47, 27.02
Venu - RL/SoB - 46.53, 26.48
Venu - VW/PB - 44.30, 28.46
Mega - VW/SoB - 41.48, 28.14
Vile - RL/PB - 43.68, 23.74
Venu - RL/PB - 42.82, 23.27
Bell - RL/LB - 39.08, 23.66
Mega - RL/SoB - 39.48, 22.47
Mega - VW/PB - 37.59, 24.15
Bell - RL/PB - 36.55, 19.86
Mega - RL/PB - 36.33, 19.74
I realize this is a lot. I'll try to make conclusions.
1) Either exeggutor is up there with vine whip/solar beam Venusuar as top grass attacker. Against Rhydon, I'd say exeggutor is better, as it also has a resistance to ground moves (which Venusaur and others lose due to poison typing) and fighting moves (due to the psychic type).
2) Tangela is very underrated. Offensively, it and victreebel are the 2nd tier. Tangela is tankier overall and, as pure grass, it also resists Rhydon.
3) Vine Whip is better than Razor Leaf as an attacker and this difference is larger when dodging conservative.
4) Meganium is a tank (again, extra resistance as pure ground) but hits like a light breeze.
5) Bullet Seed may not look too special, but Exeggutor attack stat helps it.
The value of exeggutor and tangela as grass attackers is new and, I think, underrated.
Please let me know if you have other thoughts, interpretations, criticism, questions, etc.
