Thankmar, Count of Braunschweig, is probably the most directly interesting start since you start out with the goal of spoiling Otto.
King Hakon of Norway is interesting because you're Catholic but your people aren't, and you've got someone on far shores who would love to take you over.
Alan of Brittany still has his manifest destiny to complete, and although pushing over Namsborg isn't too difficult, not getting absorbed by West Francia can be harder.
Gascogne and Navarre are small, threatened, but not untenable positions.
Hard mode would be the Sardinian counts or Duke Landolf of Capua.
I'm also doing a run as Duke (now King) Hermann of Swabia. Although expansion hasn't been on my list, just putting myself into a position where I can fend off attacks and manage my own affairs has been a doozy. I supported Thankmar, then Germany descended into rebellion and so I declared independence, sired a bunch of bastards, betrothed them off to get alliances with West Francia and Italy, used them to defend against invasions by Arles and Milan, and just became king. It's been 20 years. Thankmar got me Augsburg off Bavaria, but I haven't expanded at all.