I strongly disagree with this suggestion. Reasons :
1: The rucksacks are already extremely expensive, giving them even more bonusses will raise their prize further.
2: Because gvg is the only way to achieve them only the already heavily geared and rich people can obtain them. I think we have had more than enough changes that improve the strong and weaken the poor. Aka this change would only be for the rich people.
3: In my opinion you're asking for quite a big change.. you're trying to remove a debuff but not only that, on top of that you want to give it quite a big advantage. Yes 5%damage increase can easily make a difference, and honestly I see no reason to do this at all. Just because they are hard to achieve they should become even better ? I see no reason to buff up the already strong players and weaken the newer ones even further.
4: The GvG prices at this moment have little to do with the attendance to GvG. People don't GvG because certain guilds are monopolyzing GvG and the "newer" or "smaller" guilds will have absolutely no chance to compete. Bloo's player limit could be an idea but I doubt it will work.
You do know it will take months if not years before guildmasters would be able to give out these rucksacks to their players right ? And above all that most guildmasters are greedy as well and won't just hand out an item that would be worth more than 6000 coupons. This means that the rich guildleaders will become richer/stronger and the weaker guildmembers or members of a none monopoly guild will remain as poor/weak. In other words this change only benefits the rich.