Well, I know it sounds strange to do both of them when they are so similar. But for me it was perfect: I love to repeat a Camino (can't explain why, it's like seeing an old friend), and doing new Caminos of course. By doing the Sureste I got the best of both worlds: sometimes I was on the Levante again, sometimes I experienced the new stages on the Sureste.
I know you're no stranger yourself to do a Camino twice, or more. So if you walked the Sureste you would see your "old friend" again, but also check out the other stages. I think it would suit you! :O) The first stages from Alicante to Albacete on the Sureste are more camino-ish; I liked them better than the first stages from Valencia. Orito. Novelda, Sax - I long to get back! That's why I'll probably start from Alicante on la Ruta de Lana - around 20th of June, I hope!
/BP