I was, of course, aiming my comment at the general readership, rather than the author
The question I would ask about Midseason Replacements is "when this card works, does it win me a game I'm otherwise going to lose?"
If you have the economic edge over the runner such that Midseason is actually going to work, you probably have a big enough edge to close the game out via an alternative route. This card also then needs to pretty much guarantee you the game when it works - it's no good sinking deck space and at least $5 into a card to give a bunch of tags if you can't immediately exploit them, only for the runner to dig R&D next turn and win anyway.
In game theory the expected value of a play or strategy is the probability of a given outcome multiplied by the pay-off of that outcome. You then sum over all sum over all probabilities.
i.e. if I flip a coin and bet $1 on heads, 50% of the time I double up and win $1 and 50% of the time I lose.
So EV = (0.5 x 1) + (0.5 x -1) = 0 (i.e. it's a neutral expectation proposition)
You can apply the same sort of idea to LCGs - albeit with a little difficulty. If I play Midseason replacements I would estimate that you probably only pull it off in 25% of games (I'm talking about tournament level games against tier 1 decks and decent opposition). So 75% of the time it's a dead card.
Of the 25% you play it successully, I would imagine the runner gets away with no or very few tags about a quarter of the time - so all you've really done is drained his economy temporarily. I'm saying therefore that MSR "works" about 19% of the time, and ok perhaps you go on and win all of those games - but Midseason has only gained for you in that situation if you wouldn't have won from that position anyway with an alternative (but reasonable) choice of card.
The difference MSR makes is small. It will appear as though it leads to some big plays, but you'll easily forget about the tonnes of times it does nothing, or just confirms an already done deal.
With regard to Kate. I agree she's a little slow at getting started, but actually it's not as slow as you think. Replicator is pseudo draw and Rabbit Hole installs three copies for almost nothing and one click. It can get a lot in play very quickly and cheaply. I think Creation and Control should lead to some pretty creative shaper decks.