I made my first emp/elec because my very first character, an elec/elec blaster was just awful. I don't know how much debt he had - but it was at least a full level. (I didn't even know what those dark blue bubbles meant back then.)
I made the defender not even knowing that the heal power would be for others to benefit from - I skipped heal other and absorb pain - and had really made the character to be a blaster with a way to self heal. I had no idea there would be a power pool where I could heal myself - but then, the rate I was going, I might have never gotten there. I ended up deleting him, I was so frustrated with him. I regretted that for the longest time because that character had badges that my main would never get.
Some of us had to learn the hard way, I guess.
That was sort of my reasoning. My Emp/Ele defender was my first real character, and I continued playing him as my main right up until shutdown. I didn't pick Emp with the idea of healing other people. Well, sort of. My wife and I both played. Was was a Fire/NRG blaster. I wanted the self heals just for my own help. CoH was my first modern MMO. I wasn't sure what would or wouldn't be needed. I did not come from any other MMO, so I didn't have any of the holy trinity thinking. All I wanted was something that would allow me to be self-sufficient.
In the end, my heels really were almost entirely an afterthought. I built him as a sapper, and he was quite good at it. All of my other EMP boosts kept the team up and running, with occasional targeted heals. My Heal aura very seldom got used. Interrupted my attack flow too much.
I did go through quite a few teams where I was yelled at or threatened to be kicked off if I wouldn't stop blasting. They kept telling me I wasn't doing enough damage to matter. They never thought about the End Drain. In the end, I had so many IOs geared towards End Drain, there weren't a lot of things I couldn't completely drain.
It was definitely a chore to build an Emp/Ele up in the early part of the game, but it was so worth it in the end. Great on teams, and I could solo almost anything. Granted, soloing was almost painfully slow. Some of the higher level things could take significant amounts of time to whittle down.
Drawback to focusing on End Drain is, not a lot of places to boost your damage output. When things felt too slow, I would swap over to my Kat/Reg scrapper and tear through things.