What planet are you on and can we get an invite cos it sounds awesome. I have never played a world where there was enough defense to cover the whole frontline sufficiently and still enough offense to make progress. I have never had less than 2:1 def to off ratio either before you suggest that as the reason. Even with packet defense systems you will need to rely on sniping at times. This is a skill (albeit one the settings on attack gaps devalue) and the ability to do it right cannot be underestimated. To flippantly say split the nukes and prevent it is daft, a full def snipe will still be enough. This leaves the attacker needing to nuke noble, at which point your skilled player rubs his hands with glee and prenobles and renobles.
Well I guess I assumed competence from people and tribes, my mistake.
Consider a war between 2 equal sized tribes, let one (ours) be 2:1 D:O the other is pure O, they have 3 nukes for every 2D you have, so you should be able to defend that very easily with good organisational skills and teamwork (both much much much more important than what you consider most important [sniping trains])
Obviously you aren't going to defend if they nuke backline vills (assuming they are also attacking the front) but you should be able to defend the front perfectly easily without resorting to such tricks as sniping.
Now obviously if you decide to snipe with full D vills you can stop any train, but then you are using full D vills for sniping- given that your claim is that you can't find enough D to defend, this seems kinda wasteful, and as you say, people will move away from using trains and towards attacks with nukes and nobles (or indeed just any kind of single attack with nobles)
now playing renobling games will usually keep the village yours the majority of the time- but you can't really use it, it has no wall so you can't efficiently defend it again, they can noble it off you whenever they want to and force you to renoble, so it isn't really doing you much good, is it? Much better to simply play well and defend with defensive troops.
I will however admit that renobling can be useful (whilst much worse than defending properly if you have the defence, which you should) , but prenobling and renobling techniques are not the same as sniping trains, in fact it is part of the argument of why sniping really isn't very important at all, if you and your tribe aren't competent enough to defend correctly and need to do such things, the only benefit you get from sniping rather than renobling is the troops in the village (and on packet worlds the packet cost of a noble- but in renobling you also cost them the same thing) which really isn't a particularly large deal most of the time (especially given that this front line village now has no wall and so it is very likely to be nobled [and perhaps then prenobled] losing the troops anyway in the near future)
So from that analysis, we have that sniping is a skill that is useful if you haven't defended competently originally, that that doesn't get you much significant benefit when compared to simply renobling.
I'm not sure I agree with you that that is the most important part of the game tbh.
ratios (by this I mean like 1:2 or more turtled than that) then you should have enough D to cover nobles (the only exception being if you are in a tribe that is utterly dwarfed by an opposing tribe) if lots of players send attacks at you, then you'll need tribal D, which is totally fine because lots of people are attacking you. The skills to defending are dealing with it to get enough D in the correct place- spreading D out- i.e. don't send a whole D village in one go, rather send parts of the D to various different villages, this means that your rebuild time will be much faster. It is also about bouncing D around so as to be able to hold off even more with minimal casualties. 