+5 is what you get from Mahakam forge. This is +5 with the ability to select any card you want from your deck. Big difference. As I said twice now, this leader ability plus the two echo cards is instant consistency. You can pull off any number of excellent archetypes with it. Stockpile is a joke compared to it. You play an 8 point Vys and unless your opponent has a lock or movement card the round is pretty well in hand. If you use one of the echo cards to set a defender beforehand good luck to your opponent. Pincer is the second or third strongest NR leader, people just don’t play around with it enough to see its potential.
Comparing different faction's leader abilities is tricky, that's why i compared Pincer Maneuver exclusively with other NR abilities. But if you wanna go that way, Mahakam Forge is only 5, but then you have the passive of +1 armor to all dwarves. Also the +5 synergizes with pyrotechnician, yarpen zigrin, aglais, gord and more.
Then you mention the value of consistency offered by Pincer Maneuver, and also the 2 echo cards found in most NR decks. That's the thing - with those 2 (Oneiro and AA), you dont need even more consistency, that's overkill, its preferable to have a leader that can give you something else.
You mention the value of Vysogotta, and i think everyone agrees that's a gamedecisive card, and why everyone will try to stop it as soon as it's played. But playing at 8pt? I would rather play it at 5+shield, that way if its countered by Heatwave it hurts less. Also Rockslide is pretty popular on one of the 3 most popular decks, which deals exactly 8dmg, while if it had a shield, it would be protected for 2 turns against most things except SK and ST Precision Strike.
Im sorry but i disagree, Shieldwall, Uprising and Zeal are clearly better, and i would say Mobilization and Meve's ability (cant remember the name) are also better, Pincer Maneuver cant do anything that other NR cards or leaders can do better.