If it's no problem, I would like to see a champion of each attribute being shown as a free champion. At least one assassin, at least one tank, at least one fighter, at least one mage, etc. However, I hope that a bit of variety is given, by showing completely different champions of each attribute each week. For example, showing Fiddlesticks as the jungler for one week then Volibear for the next week. The first has a mage jungler, and the following week has a tank jungler. As for tanks, maybe Leona and Alistar. Very different champions, yet of the same attribute.
This way, new players can find out that all champions are the different even when they are of the same attribute. One tank is completely different from other tanks. A jungler doesn't have to be the same as the other jungers. A fighter can be squishy, or tanky.
Also, having at least one of each attribute will allow players to try out all the attributes every week, before finally deciding on their playing style.