Yes, of course the boots are an odd piece, favoring defense over attack unlike other Bandos armor, but it's dragon boots that warp the picture, having perhabs higher str bonus than they should at their level and rarity. But a full rebalance of boots would take much more thinking and effort and any nerfing of dragon boots would certainly enrage a large part of player. Also it would feel awkward for Bandos boots to have double the str boost of Bandos tassets, and I don't know if this would be a good idea to increase theirs. The strength of my advice lies in the simplicity and harmlessness of it. +2 str would be very in place compared to other boosts from Bandos and will not obsolete other boots. Also, they will become less strictly worse than Dragon's and sometimes even on par. If +4 str vs. +1 def/+1 prayer was a no-brainer, a +2 str vs +1def/+1 prayer is less obvious. Don't forget to consider the better looks of Bandos boots when weared with the set, and you will see their use will increase.