Suggestion for tank battle tiers

Lert: Would necessitate a rebalancing of biblical proportions, as the tanks are designed to fight with the tiering they have now. The last time we had a narrowing of tier spread many tanks lost their top gun, and many people still whine that and have yet to forgive wargaming for 'ruining their favorite tank'.   The only change I would make is that tier 4 would see +/-1 instead of +/-2 like it does now, with some exceptions like Matilda and Hetzer.