Well, I agree with you on the wars.
As a matter of fact, I utilized the individual opt out, as soon as it was available, with the kind permission of my ally leader.
Wars interfere with my real life, and the rewards are most definitely not worth the effort, nor the annoyance of scheduling your real life around a mobile phone game for the mid-week battle.
(I am on Central European Time, can play with reliable internet connection only from home with WLAN, and had to schedule my attacks for the mid-week battle for 23.30 on Wednesday evenings - during the work week, no less. That does get very annoying very soon.)
I used my 3 Merlins when I still participated in wars. They did a good job - with my other purples - especially against opponents who use guin tanks.
Some players love wars, others consider them an unwelcome duty. That is just the way it is.
I, for one, am very grateful to SG for introducing the individual opt out. So that those players who detest wars do not get annoyed enough to leave the game. Such an option is beneficial for customer retention
Back to the thread subject:
Merlin is great for pvp, for events, and for wars.
If you are lucky enough to have several merlins, and you do wars, do try and level up several Merlins for wars. He is very helpful, especially against yellow tanks.