Unlikely. I don't think I ever flew on the IOM to STN route on a plane more than a 3rd full, despite what are usually the cheapest seats to London at the moment. There are a number of reasons for that:
The Manx economy is ok but it doesn't support the level of business travellers pre-2008. The Financial Services industry (and no I don't specifically mean the newspaper-villan "bankers") is still in a position of tightening costs. The supposed space industry appears to consist of a 30 brass company names on 4 room run down office buildings with 30 registered company names (slight exageration). The gaming industry is extremely profitable, but relatively low on need for travellers. Many, of what affluent business travellers there are, want to fly to City but there are barely enough to warrant that flight, even with hard fought underwriting from a local business.
The tourism industry is minimal despite the best impression that the governments tourism board tries (and fails) to set. Theres little money in the government coffers so they even resorted to making a big deal out of "dark skies" tourism. Thats where the tourism board saw that it was free to nominate dark sky locations and did it enmasse before anyone in the UK. So government sponsored adverts/articles went into national newspapers suggesting to Britons that there are more dark skies than the whole of the UK put together. Actually they just got there first and the skies are no darker than the countryside in the UK. And, more importantly, how many people really go on holiday to somewhere based on their dark skies at night. Really, the countryside is oustanding but the towns/villages are generally unappealing compared to the UK and the weather poor - you may as well drive to countryside elsewhere in the UK for less effort and cost. Its not sunny and warm in the summer like Jersey. Its not sunny and warm like the south coast of England.
Realistically, Manchester is preferable to Gatwick for a large proportion of Manx residents. Thats for UK connections and connections to the rest of the world. For those people that do fly to London for connections, they're wanting alternative or cheaper connections to Manchester - Gatwick offers the best options and Luton wouldn't be better than Stansted.
Easyjet. Big name, big airport in London. A more comfortable flight on a jet than all the props Manx people are used to - FlyBe, those Let410's operated for CityWing etc. There are usually nearly full flights from Gatwick. The Luton flights on Aer Arran and FlyBe were never that full.
There have been many different UK routes tried to the island - the island just cannot sustain them. Flybe couldn't attract people to Stansted with very low fares. It would be much more convenient for me personally but I can't see there being the numbers to support a Luton flight. They can try but they're unlikely to succeed