[Taneli]

That is a good question. As a GM on a table where this issue would pop up, I think I would rule that this rule only applies in situations where other game mechanics can't produce sufficient results by themselves.

So, my feelings on the specific topics in order of your list.

1) No, missiles and jets themselves are subjects of the spells, not the targets

2) Maybe, the targets are the subjects of the buffs and weapon buffs. SM for equipment is a bit dodgy, but if it's smaller in volume, weight, and longest dimension, it's generally smaller than you. I might be persuaded to agree on only two of three, like in the case of a very long rope.

3) Again, maybe. It's difficult line to draw. Is the missile just a special effect, or the actual manifestation of the spell?

4) Yes, I agree with you here.

5) What about some grass trying to grapple a giant whose feet are the size of blue whales? SM limitation makes some sense here.

6) Innate attacks would still work, other spells maybe not?

7) I would consider that the one getting the information from detect is the primary subject, and the detected things are just targets (that might be protected by some means), so SM rule would not apply.

8) As per the SM-rule, no. But that produces silly results to me.

9) If the spell description allows to only affect a part of an item, I would rule it to be OK as longs as the affected part's SM is no larger than the caster's limit. See point 2 for my Q&D size parity approximation algorithm.

10) The ogre is not applicable subject for the spell, so I wouldn't count it in in any way.

11) Yes.

12) As with Detects, I would consider the party that gains the knowledge to be the subject, and the target to be, well, the target.

13) That's a tricky one. Although, I might argue that the subject of dispel is actually the spell, and not any physical entity. Do spells have SM's?

14) Does the spell make the halfling look scarier or the beholder more scared of the halfling?

15) I would rule that Telekinesis is more like missile spells. If your TK ST is enough to lift it, you can lift it regardless of it's SM.

16) I feel that the rules without the SM limit give sufficiently playable effects, no need for the SM rule.

17) Thunderclap's subject is the point in space, and the effects are just what follows naturally, so no SM limit. Similarly on Turn Zombie, assuming the world has such "natural laws". If it instead changes something in the zombie's mind, I would rule that the SM rule applies.

18) The one protected by the spell is the subject.

19) I would rule that the spell affects a point in space, and the recipient's presence is merely a trigger that activates the replay of the message. With full on Telepathy, the subjects would be the both ends of the conversation, and SM rule would apply.

20) Well, the subject of the spell is clearly the weapon, not the one being hit by it.

21) World creation issue, I would default to the one who is actively making things happen, that is, the user, but an interesting variant would be user's SM + Creator's Talent.

22) That's a tough one. Probably not, but I would rule 0 that out of the way.

23) Uuf, trixy little halflings! Can't decide without an actual example.

24) My gut says yes.

As a general rule, I would keep this SM-rule in and the relax it on a case-by-case basis when I feel that the rest of the ruleset is sufficient to handle any issues. I don't think that you can have an easy fix for this. I guess that it was left in for cases where a cheap simple spell can cause massive issues down the road.

Also, I don't think that an FP cost would the the Sorcery Way of solving this. FP cost is more like a limit on the number of spells you can cast in a given time frame, and not a power balancing thingy for spells, even though some spells defy this (like healing).