The whole point of operating with the brigade is to defend that brigade that might be spread over a significant area. Having missiles with an effective range of only 5-6km simply doesn't cut it... especially considering that some of the IFVs will have MANPAD gripstocks anyway.
I don't see a problem to place Pantsir on another vehicle if they don't like current one. They could place it on new Armata chassis for tracked version and on new 8x8 vehicle for wheeled version.
They are going to have to anyway... there is no point spending all this money on an Armata brigade if you have non armata vehicles using different engines and transmissions and other components... the idea behind the armata brigade is that you need to support one vehicle type with one engine or related engine family with standardised components and the result is a group of vehicles with the same mobility and protection levels that can operate together.
Having the vehicle that protects all the other vehicles with very thin armour is just asking to be taken out first... leaving the whole unit vulnerable to air attack.
Well, 45 mm gun is far larger gun than 30 mm one. Placing larger gun on a system like Pantsir, it means you have to take missiles away or to place few smaller ones like Igla. Similar AAA systems like German Gepard, Polish Loara, Japanese Type 87 and similar Chinese one, equipped with Oerlicon 35 mm gun are without missiles. Germans with modernization place two Stingers on Gepard. 45 mm gun is even larger than 35 mm gun.
Yes, that is why I suggested a separate vehicle... if it is chosen over the 57mm gun (and I think it will because of ammo size) then it will likely be the standard IFV gun, so adding an IFV or perhaps 4 to the Pantsir-S1 unit you could fill the troop compartment of the armata based IFV with auto ammo handling equipment and perhaps put a few hundred rounds in each vehicle. The Pantsir-S1 vehicles wont need their 30mm cannons which should make them smaller and lighter and cheaper and they could direct the IFVs to targets that the IFVs can mark with their own lasers and engage with guided ammo.
Using a large gun and MANPADS is not really an option because the 45mm gun could probably engage targets at greater range than the MANPADS... the missiles on the Pantsir-S1 and indeed TOR would be far more effective.
Of course a redesigned Pantsir-S1 with a single 45mm gun down the centreline with a fixed four faced AESA array on the roof that combines the search and tracking functions of the two radars currently used with 12 missiles attached to the sides of the turret could easily be an option too, though that would require a rather wider turret to accomodate the gun and its autoloader and internal space for shells.
Note the 45mm guns shells will look like very long cans and will be fairly compact and easy to store and handle.
Russia already have similar turret from MT-LB-6MB5 upgrade with GSh-30-2 gun and Igla missiles. This turret could be also placed on BTR-82A or Vystrel vehicle. They could increase number of Iglas from to 2 to 4 and could get good light VSHORAD system for lighter brigades and could work well with Barnaul-T.
MANPADS are a last resort for vehicles, they are of course better able to use their performance than when carried by a man, but when you are relying on MANPADS you are letting the enemy get very close. It makes rather more sense to use something like SOSNA-R with a very high speed missile and 8-10km range, than a MANPADS.
I appreciate that for the light brigades, when working with 10-12 ton vehicles then something like Phoenix with MANPADS and 12.7mm HMGs is probably the limit in terms of weight, but for a 25 ton vehicle in a medium brigade then you need range and reach and power.
Iglas were used as an upgrade for the ZSU-23-4M4, but they are only intended to offer an air defence capability while the gun ammo is being reloaded and I suspect that is the same for the Gepard.
The point is that with the Pantsir-S1 the idea is that both systems, missile and gun are to be used as required with each supporting the other.
In the medium level vehicles it might make sense to separate the missiles and guns to reduce weight. For the heavy vehicles they probably wont need to, though the anti aircraft performance of the 45mm guns might make its use worth it, but I would still prefer separating the gun from the missile if they go for the heavier calibre gun... it all depends on how heavy and complex a four face AESA array is as its replacement of the search and tracking radar should allow much faster 360 degree electronic coverage with no moving parts and would free up the front of the turret for a gun which means the 30mm guns could be removed and the design adapted for the new 45mm gun (with guided shells one gun would do...)
For the light brigades pantsir-S1 would be too big and heavy... remember the tunguska is 34 tons. An 8 missile system on a kurganets or boomerang could be manageable but to squease it into a 10-12 ton platform... they might go for a single 2A38M 30mm twin barrel cannon and 4 or 8 SOSNA-R missiles, or they might go for Morfei or 4 x Pantsir-S1 missiles...