Sport is tribal (my team at war with yours), brilliance (a great goal, a stunning catch), hope & despair (my team's performances), schadenfreude (your team's performances), something to talk about (with family & friends), surprise (Webber & Vettel), drama (Zidane & Materrazzi), unpredictable (unlike a soap opera), charming (Roger Milla's goal celebrations) and ugly (Gary Neville).
I much prefer team games - football (Chelsea) and cricket (Sussex), in particular - because there is something important for me about different skills and tactics amongst the players (bowler who scores a century, striker who saves a goal). In comparison, tennis and athletics look like people doing one thing over and over until the superiority of one overwhelms the other; I know this is a simplification but I just don't get the same buzz from watching them.
It seems to me that no relegation mostly benefits the incumbent owners (the main advocate in English football is the owner of a Premier League club usually at risk of going down). The excitement of potential promotion and danger of relegation are great motivators for fans and players alike, something I would hate to see lost.
The increasing domination of the European leagues by a few clubs is a worry (big four in England, Real & Barcelona, Bayern, etc.) and I would like to see some way that could be evened up (salary caps, draft, whatever).