Tony Vargas
Legend
18-24, or 12-24, if you conceded the possibility of 2-round combats. :shrug:The default assumption is 6-8 encounters. Being generous 3 rounds that is 18-254 rounds.
Specific action grants are pretty situational, by nature. The other two actually mitigate against eachother more than you might think. A daily resource that lasts 10 rounds, even w/concentration, used in combat, is pretty likely to go the whole 3 rounds, so you'd only need to accumulate 6-8 of them, not 12-24, before they became functionally as available (in combat, that is) as an actual at-will. And, from other threads in the 5e forum, it seems like 6-8 encounter days aren't exactly something you can count on.The spellcaster ones are also situational, require daily resources and the concentration mechanic.
Ultimately, though, whether you expend a resource for it or not, an action-grant that costs the same action is pretty neatly balanced. Obviously so, in terms of the action economy. But, even in terms of doubling-down on whatever the best action that round may be, it comes out more flexible, but less potent, than simply adding a second character able to take valuable actions, himself. For instance, D&D traditionally had a spell/round limit (3e broke with that tradition, obviously), so granting a caster an action that can be used for spellcasting (far more powerful than granting an attack or cantrip, obviously), seems as powerful and game-breaking as that forbidden 2/spells round. Yet, if instead of an action-granting character, you simply added a second caster, you'd have the same 2/spells round, /and/ twice as many slots.
So, no, action-granting, even action granting far in excess of what the Warlord traditionally was able to do, isn't inherently broken in 5e. 5e's balance is simply looser. It's hard to imagine anything a Warlord might do that could be any worse than what casters already can.