You are missing the point that [MENTION=42582]pemerton[/MENTION] was originally making. It's not about a choice of adding or not adding Minor actions. The actions are already there - look at Spiritual Hammer in the playtest rules; it already has a minor action attack. Singing "la, la, la" and hoping it will escape everybody's notice isn't going to work - the king's suit is decidedly see-through.
But Spiritual Hammer doesn't work like a minor action. There is no limit on how many Spiritual Hammers that a cleric has up at a time. Nor is there any limit on other actions that you can or can't take because you have an active Spiritual Hammer.
The problem with minor actions aren't that you can do more than one thing on your turn. The problem is that they provide a limited resource of minor actions, thereby forcing players to think about which minor action is optimal. As you note up thread, that can create some interesting resource allocation gameplay. IMO, it's not worth the time or headspace.
Instead, the designers have come up with some ways to get the benefit of a minor action without the rules concept. Spells like Healing Word take up your action but let you make an at-will attack. Spells like Spiritual Hammer have no limit other than the character's willingness to use up a daily spell resource.
Lastly, I disagree with the more general theme that broad rules are better than narrow rules.(*) Yes, it's cleaner in a software design sense to have a broad rule like minor action that applies to a number of powers. But this isn't software. There is significant overhead in teaching new players when there are additional concepts and vocabulary that need to be explained before the new player can read his character sheet. Concepts like "minor action" (or "shift", or "immediate reaction", or "dazed") add a level of indirection that make the game easier to debug, but harder to understand.
On top to this different ways of presenting the same rule doesn't necessarily produce the same result. Presenting three different types of actions (standard, move and minor) is more difficult to understand than a single action and a movement allowance. It also, in my experience, provokes a heavier emphasis on resource allocation over in-game fiction. I don't think there is anything mathematically inherent in these rules that produces these effects, but I've observed them in my players. This isn't a question of whether they can "see through" the king's suit. In my playtest experience, the different presentation produced a different result.
-KS
(*) I'm reading this theme in this thread. I'm not accusing you of adopting "broad over narrow" as an absolute position.