I've always thought of producing an XC game oriented around NCAA D1 cross country could actually be insanely fun IF implemented properly.
Characters could choose an individual or team career, and select teams with premade perks or create an entirely custom team. They can choose what region they want to train in (runner's heaven Oregon vs. hot and dry Texas) or what altitude. You'll start by training freshmen-level recruits and there'll be a selection of the All-Americans from the two years. (New copy could be released every two years.) Bonus players include elite runners like Rupp, Bekele, Farah, Gebremeskel, Lagat and other track stars.
Ultimate goal? Train the team to win the NCAA championships and by selecting a few meets per career.
Base season = boring. You can probably compensate for the lack of implementing a boring base season by using "points" that you can attribute to a runners strengths before the competition training starts. Certain credentials such as your coaching reputation will determine how many base points you have.
Competition season = select two work outs a week from a wide variety of workouts. Training knowledge is necessary to understand what workouts you should be doing and when you do a workout you can implement moving the two control sticks back and forth. You'll have to gauge the pace you want your runners to train at. Too slow and they don't receive the desired benefit, two fast and they crash and burn and increase the chance of injury later on in the season.
Race season = No one expects a player to sit on their butt for 25 minutes to watch their avatar run an 8K (but I suppose this could be configured in the options menu.) Like a race, you must gauge how fast you want to be running at particular stages of the race. You might run for 2/5ths of the race where you'll take periodic jump cuts every 600 meters to relieve boredom. While you're running you can implement drafting, surging, uphill running, downhill running, turn running, passing, getting passed, psychological stress and perhaps you could get the bonus "endorphine rush" if you put all the factors in the race properly?
During the race if you're on a team you can switch between five of your individuals, with the sixth and seven individuals being automatic unless they become the fifth individual. 75% of the race will be spent controlling your anchor man, with the other 25% allocated evenly among your other four racers. When you switch from player to player, you put the prior player you were playing on auto mode and how fast they run auto mode depends on gauging your speed when you leave them off. A pace marker in the upper right hand of the screen can tell you how fast you're going and below that pace marker can tell you the runner's PR. (Example: 24:30 pace when the runners PR is 24:55 indicates you should slow down a bit or implement better racing techniques.) Bonus points if you maintain an even pace. Your training techniques will come in handy here. When you train to accomodate a particular course, you will be able to run faster due to specifying how you want to train.
The racing will still be too boring for even runners to accomodate, so this can be mixed up with multiple camera views, realistic breathing, aggressive NPC AI, and an unrealistic blurring affect of the scenery around you. Weather can play a roll too. Spectators can be shouting mile splits (imperial distance to appease the masses.)
Placing higher at meets = more money allocated to the XC team. More knowledge on how to train, plus equipment benefits such as underwater treadmills, massage therapy, but the competition gets stiffer as they look out for you as a team and work to defeat you. You can also purchase better shoes for your players, ranging from training flats to Nike Victories that can give a full 3% time boost.
NCAA Championship = dependent on the difficulty level, this will be a moderate to extremely difficult meet to win. The course should be randomized and given information to the player at the beginning of the season so they know what to train for. (Example: Training for Terra Haute requires training to maintain a steady pace for long periods of time due to Terra Haute's gradual turns.
Online can be fun as you team up with other custom made teams to race in meets and compete. And as aforementioned, bonus players can be purchased when certain requirements are won. (Example: German Fernandez requires winning NCAA on easy mode. Galen Rupp on difficult mode. Mo Farah or Bekele on elite mode.)
I think that this can be fun. It won't sell awesomely like Madden (not even close), but I think by adding flashiness to the players while maintaining running intellectual integrity, you can have a fun game for newbies to experienced runners.