Honestly, you dont even need a single merit in group 2. The BP's are not good for endgame. Yes, if you get your avatar 300% tp then use them, they can do decent dmg. But by the time it takes for say shiva to get 300% tp via attacks on lvl 85+ mobs, considering the Miss rate dampering tp gain, you can just use garuda and pop predator claws non stop and out do what ever u were going to do with shiva 300%.
Depending on how your linkshell does endgame, and how many mobs you kite can affect it. If you fight alot of kited mobs, go avatar attack caped, avatar magical attack capped. THis way your diablos nether blast dmg will be up since thats the prime power hitter on kited mobs. If you dont fight to many kited mobs, overall going pet acc and pet att will help you in all aspects of summoner. sh*t like ixion, sandworm NM's ect, with my merited acc/att my garuda does around 500-700 average, then about 1/10 ill break 1k.
Make sure to merit smn skill. 8/8smn skill turns to 16pet acc/ 16pet att. Thats the single largest merit boost to smn you will get.
MP is ok to merit, but not needed by any means. If you have adiquit refresh gear, and a refresher that should be enough, combind with siphon, to never have any mp trouble.
SMN, in my opinion doesent need that much merit attention, since its so damn good right out of the box, its hard to make it much better then it is.
For endgame focus on gear in this order SMN Skill > pet acc > pet att. Other then that get mp / refresh pieces.
The Lv.75 bloodpacts are worth having, and do give a summoner yet another way to deal magical dmg other than tierIV's. The real deal is that as long as your a summoner in a LS of other job classes, you will always be a second class citizen.
It's when you put a party of summoners together that you see a combined power that gets great results. I dsagree with your statements about not needing a 75bp because I use them and they do great dmg. And my Lv.5 thunderstorm is stronger than predator claws against alot of mobs. Too many players just use predator claws on anything, even mobs that are weak to magic.
Thats were my Lv.5 thunderstorm shines. Its still not as good as a blm but it does the job.
Sylph: San d'Oria: Rank9: Hume: SMN:Lv.75.
[Geocrush][Heavenly Strike][Thunderstorm Lv.5][Meteor Strike][Wind Blade][Grand Fall]
LFG:COP 5-3, SAN D'ORIA 9-2