The stats of Zwei and its stuff are almost perfect I would say.
The only change I would be happy with is if the 2h skill got a buff but with that, the 1h skill got a nerf. With this same concept with Leg buff 1h nerf 2h.
To point out why sentry should stay the same or could even do with a buff in some area's is to compare it to Mara or even Hoplite. Sentry is the pinnacle of a glass cannon in Ni having the lowest armour out of all 16 heroes but unlike Warden, its class is not meant for ranged it meant to be on the battlefield (in some cases). Even then its a 2h, not a 1h so you depend on others to be your shield.
The only change I would be happy with is if the 2h skill got a buff but with that, the 1h skill got a nerf. With this same concept with Leg buff 1h nerf 2h.
To point out why sentry should stay the same or could even do with a buff in some area's is to compare it to Mara or even Hoplite. Sentry is the pinnacle of a glass cannon in Ni having the lowest armour out of all 16 heroes but unlike Warden, its class is not meant for ranged it meant to be on the battlefield (in some cases). Even then its a 2h, not a 1h so you depend on others to be your shield.