I don't want to sound like a smartass, but I think most of you don't know what are you talking about. You remind me of those feminists, keep looking for changes, without realizing those changes lead to a lot worse situation overall. You just don't see consequences.
From my experience from other similar sim games, buzzerbeater is by far the best system out there.
basketism:
You pull 19 young players per season, instead of buzzerbeater's 3. It leads to the situation where trainee has to be top-notch, or he's useless. Imagine everyone getting 18y hofers with 60+ TSP every season. Would ruin the game.
You train all players, instead of one/two positions. It leads to the situation where all players have good skills, so they are devalued. Imagine everyone having full roster of 130+ TSP players in buzzerbeater. No diversity. NT experience becomes a deciding factor for player quality. Managers are sacrificing skills in a mad race for experience.
trophymanger:
There is a 5 star system, and litterally every player trains, regardless of playing matches or not. It leads to the situation where 3.5* or less players are basically worthless. Every team, even lower leagues has 4* or better players. For 5* players, difference becomes playing for NT or not, where they gain routine. There are tons of 5* players in large nations who don't reach NT, so they remain pretty average, bloated salaries, and no routine to stand out.
They made "bloom periods", so players do most of their training in 3 seasons. Then they made training grounds too expensive, so if you have them, what you're supposed to do? Buy 30 players let them train without ever using them in matches, and then sell. It's like you're growing domestic animals, not human players.
Basically, these games have unstable systems with issues. People start to whine about these issues, they fix the issues but creating more issues, then people whine about new issues, and so on.
Anyway, rant over, back on topic:
Why would you buy a high level trainer, when you can train a 120+ TSP player with a cheap level 3 trainer?
I have always been saying, level 3,4 trainers are most efficient for training. In special case, if you are willing to sacrifice your team to build that uberman monster player, go for level 6-7.