First of all, Oak's shield is a totally different thing than QoT's shield. Oak's shield has a much longer cooldown, but after you get Shield 3, it also makes you immune to interrupts. Oak's shield is a getaway (Shield then run, or shield then teleport), while QoT's shield is a spammable damage immunity (for a certain amount). They both do their job pretty good.
So stop comparing QoT's shield with Oak's shield, it doesnt make any sense.
Secondly, No demigod is supposed to endure 3v1 under normal circumstances. If it does happen, it means that this demi is OP, or simply playing vs bad players.
QoT should die when 3v1.
Lastly,
You answered without really thinking about it.
I dont need to think about it. If you want to give her 3 sec Cooldown on shield, then might might as well make it absorb 3000 damage to make her 100% unkillable. Your suggestion is a totally unbalanced QoT.
If you want to make a logical comparison to QoT's shield, compare it to Sedna's Heal.
- Heal has the same cooldown as shield.
- Shield is better early game, but Heal is better late game because it removes debuffs, and so it scales a little better.
- QoT's shield is an instant cast, while Heal is 0.5 sec cast and it can get interrupted with good timing and lot of luck.
- Shield lasts a few seconds, so you can shield an ally, and go to farm another lane, or go to shop. While Heal restores some HP, so sedna will have to be around to that.
- Both of them cost about the same mana (mostly)
If you want to make an arguement about Bramble Shield, at least make it so that it makes sense.