I'm not well placed to argue about tokugawa's strength in warlords since i never played him, but if I had to play him, I'd try to draft mountains of rifles (or even muskets) for the free combat 1, drill, CG 1

.
To the OP : A few questions.
1) what do you call high levels?
prince is a medium level, monarch arguably too.
2) what do you expect?
if you want an early UU able to crush your neighbours, I suggest playing one of those leaders :
- augustus or JC
- Cyrus
- Huyna capac
Be aware that the praets require iron, the immortals require horses and the quechua require your enemy to rely on archers (which is exactly what the AI does

)
3) what's your goal?
- winning a deity game? as cheesy as it may be? play a duel map with huyna capac. build quechuas. win.
- improving your skills? You're better off playing various leaders and trying to max out their potential.
- having fun? Play on a level where you're somewhat challenged with various settings/players for a renewed experience without needing a climb in the levels.