
skizzerz |

The only time boosting a d4 skill is really nice is when the check is commonly a 5. This pretty much never happens for a base skill though, and you can't put skill feats on skills absent from your character card (such as Divine). A +1 is also helpful if you're using it a ton and can barely eke out success even with blessings, but that isn't going to stop you from needing to spend blessings on it.
In all, it's likely not worth doing.

Irgy |

It's optimal in some sense, in that if you're rolling a d12 then a +1 helps 1/12th of the time, while a +1 on a d4 helps 1/4 of the time. Add more dice and the difference only widens.
The problem is that as a d4 skill you'll simply choose not to use it most of the time, and there's almost always an alternative. Often even a skill you don't have is a good alternative if there's a card that adds dice to that skill somehow.

Nefrubyr |

I've been playing a solo Athnul through Rise of the Runelords and I gave her d4 Int a +1 feat, mainly to boost her chances of acquiring potions and other items with an Int 4 check to acquire. In that case it pushes a 25% chance of success up to 50%. It helps with those Int 6 or 7 checks to close too.
This is really a case of rounding out a solo character. With a group of two or more, I'd concentrate feats on characters' better skills. Also, RotR is relatively easy so I sometimes go for feat choices that are fun or interesting rather than optimally powerful.
I think I've also put a feat on Lini's d4 strength in the past, but I wouldn't really count that because it turns into a d10 or d12 (depending on which version) when you need it.

Rebel Song |

I'm seriously considering adding a skill feat to Myrtle's Dex, since most of her combat items work off her Dex. :/ But I want to add to her Wisdom and Intelligence also. Argh.
My boyfriend's Ranzak took ALL of the Wisdom Feats. He was automatically defeating ships, it was crazy.
I think it depends on how your character works. If you change that d4 into a larger die often enough (through stat stones or spells or other powers), it might be worth it.

Longshot11 |

As with Ashram316, my wife plays Ranzak exclusively and always takes the +1 (or more) to the wisdom check. It comes in handy for that particular character who also has survival tied to it.
Same with the GF. I think we were 2 feats into Dex, before going all-in on Wis.
Also, I've considered it as a Wis upgrade in RotR for Valeros. Yeah, it doesn't beat any checks by itself, but Wis comes up pretty often (Cutpurse, Sneak, Woods, friggin' Mountain Peak and Siren!) since I'm throwing in a blessing/Sage anyway - the hard bonus goes a long way. (This would actually apply to any hero's dump stats, but compared to Wisdom, Merisiel's d4 Intelligence just doesn't come up statistically often, for example)
Depending on your build, upgrade to Lini's Strength can also be a wise choice, as people've already mentioned.

Codcake |

In RotR there are many wisdom/survival checks to close locations and with Ranzak's ability to quickly burn through cards it became obvious to dump skill feats into the d4 wisdom. Plus being able to temp close a locale without having to burn a blessing by using a Sage helps out for the villain checks.
The wife and I went through RotR with Ranzak and Ekkie with little to no difficulty. We had a blast aswell.
Cannot wait for Tup in two weeks, and all his compadres in August.
"Can't wait for shoppin'
on more of us Goblins?
To bide your time,
Go throw some die!"