The spreadsheet below looks at a typical choke point. Two Turrets - One Black Ice - onto a Scanner. The spreadsheet is balanced and looks at nodes and programs of the same level. I've only been able to go to level 11 due to wiki not yet completed.
Spreadsheet explained.
A - Node Level
B - Protector Strength
C - Sentry DPS
D - Turret DPS
E - Black Ice DPS
F - Total DPS (sentry*3 + Turret*2 + Black Ice)
G - Seconds which Protector Holds
H - Turret Firewall
I - Guardian
J - Beam DPS
K - Time Turret Holds - No Guardian (Firewall / (Beam DPS*2)
L - Time Turret Holds - 1 Guardian (Firewall + Guardian / (Beam DPS*2)
M - Time Turret Holds - 2 Guardians (Firewall + 2 Guardian / (Beam DPS*2)
N - Time Turret Holds - 3 Guardians (Firewall + 3 Guardian / (Beam DPS*2)
By subtracting column G from columns L, M or N, you will see that a second Protector is not required with no guardian. Having a levelled guardian means a person has to add another Protector.
It's interesting that Protector gets stronger. A case could be made for a Nerf. However, time factor is an issue in balancing. Whilst less time is needed on a choke, at higher levels we have more gates and more nodes. Therefore it's actually in keeping with what I would expect. And is balanced IMHO, but would need to be compared against other factors.
I also do not take into account Guardian re-adding another shield if time allows. So I would expect times to actually improve in real time defence. But it add another level of difficulty to the spreadsheet, which at this time I can't be arsed to do.
