Skill books

P2W players are actually looked down upon, because nobody wants a game where if you pay = win without opportunities for the F2P players. I’m personally a P2W player here and I’m not complaining at all about the skill books. In fact, I’m actually enjoying them a lot because there were many generals in the game that had potential, potential which I can now make them achieve.  Don’t hide the fact that you also made good use of the books, with your Ivanov, especially.
The IAP bonuses are there to balance between the P2W players and the F2P players. Skill books are around, sure, but the IAP bonuses are all quite good. 
If you feel that making the skill books more expensive will balance it, then let’s not make it ridiculously expensive. 25 books for the first skill change is way too much if the price will increase in the same scale that it currently does. Remember that after you get all one-time rewards, the only sources of skill books are ads and the shop. I’ve already calculated that the price for just the first change would be 1125 medals, not counting the ads that I consider unreliable. 
Medals might be everywhere, but unlike 1806 you don’t get medals if you redo a conquest. So after you get all one-time rewards the only source of medals is Ludendorff's IAP bonus. If you propose that price change, skill books would become a P2W-exclusive feature pretty soon and it would be all F2P players complaining that the P2W players can make as much demigods as they want instead.
Believe me, this thing about P2W players having unlimited power and the F2P players having nothing is an issue in many gaming communities, and I would HATE to see it happening in this great community that we have here. It would divide it: On one side, we have the F2Ps that complain about ET games being cash grabs because the game is unbeatable. On the other side, we have the P2Ws advocating that the game be more P2W-heavy because they want to spend money and don’t care that there are people that want to play the game without spending a dime.
In my opinion, the IAPs should be this: Completely optional because having them won’t give a giant edge over the F2Ps, but also worth it because the features that they bring along are good.

They will once the only source of skill books become the shop and the ads. With Lud's bonus, that means a guaranteed 1 skill book per day, with 5 leftover medals.

Do you buy those?

You click on the little wheel that you have next to the “Like button”, then choose “Delete” and confirm that you want to delete. Bingo.

Sorry for answering, but upgrading tactics, which are a major feature, sounds like a nice thing. If anything, the boosted tactics cards are quite cheap. 
The Motorcycle is basically a slightly better ambulance. Its value comes from the fact that we now have 1 Ambulance and 3 Tents instead of 2 ambulances and 2 tents, and by having the Motorcycle, you can essentially break that change by having 2 Ambulances and 3 Tents.

It’s not too much of an edge and it brings a good feature for the P2W players. Seems fair to me.
BTW, according to the chat, the upgraded tactics IAP is one-time use only, therefore seems like a waste to get it.