10 draft players for 100 rank points? Is this normal? 100 rank points expensive

Yes, that would be a great addition and in fact suggested by quite a few posts already.. hopefully EA picks it up as there is some revenue to be made as well Dr selling some transfer points just like the training.

I understand, but it would be much easier if you could take away the rank points from the players, say you would get back half of what you can no longer play, e.g. a 115-116-117 player won't be good in the later ones, and a player with a max rank of 120-121 is already weak in the champion.

My strategy is always rank to red(Level 4) first all the players and go for gold only when I have spare resources.  Think of it as a 2 to 3 season investment when you spend Rup points.  Often, You don't need the last gold rank up.. the players play alright even without it.

It has nothing to do with the tenure of playing. Rank Ups are a relatively new concept to the game after URP cards have been discontinued, so we all started with the same amount of 0, not so long ago.  I just didn't waste RUPs on every card claimed, only my themed team players. Resources are scarce, gotta manage them better or struggle with being able to use them when required. 
Also, watch your tone.

Not everybody play many years man 

There is a lot more given out than we had at the start, there could be more, but thats at EA's discretion.
Grind all events, do the other exchange with 450 OVR (there are smart ways to save the coin there, I'll let you figure it out). And there is a lot more than the 300per week you claimed.

I have been ranking up a fair number of players in the recent weeks, and I still have 30k RUPs left. I guess my resource management as F2P is a bit better.

but what should I do with 100 rank points? scouting camp 200, event maximum 300 per week, weeks by the time you rank a player up, he will be outdated, maybe he won't even be good for your team with maximum performance, you wasted your rank points, it will take 3-4 weeks to accumulate. and then the next week comes and a better player again, this is incredibly pointless.

Use the other rank exchange, the one you are looking at is ridiculously expensive, you also have some coming in the weekend cup and in the resource pack