From the views here I think some have been in aviation all of 5 minutes. Loganair operated very succesfully into Oban in the 70's and early 80's with Tri's and Bandits, not even an NDB in those days.
Huggy, do you even fly into Scotland? Many airports up here do not have an ILS, sheer luxury that is you know! Take SYY, NDB/DME only, and it is a very active Diversion airfield for Transatlantic & military heavy stuff, so it does not trouble them having no 'fancy' ILS! Indeed the 'capital' of the Highlands has only VOR/DME.
Isle of Skye? Anyone remember that NDB approach? Right angles to the blooming runway that one, all due to terrain. Again Yogi operated into there with no great dramas in the past.
Oban has a wee hill at one end, and not much in the way at the other. Weather is just not a factor for the type of aircraft which will use the new facility. Many of the smaller islands like Coll and Colonsay have no aids at all, but it is a very succesful type of operation in the northern isles.
Plans are quite advanced for Oban in anycase. The concept is to use Oban as a 'hub' for a future Inner Hebrides air service, linking the little islands through Oban to either GLA or PIK. Most likely the venerable BN2 will be the aircraft of choice, giving way to the C208 when SETP ops are eventually approved.
Subsidies are available for some parts of the operation, so it will happen!