Whilst I think the existing flights from Inverness to London airports such as Gatwick and Luton are good, there is no getting away from the fact that flying into London or via London through Heathrow opens up huge additional possibilities, particularly as Heathrow is the UK's major international 'hub' airport. So the news that British Airways is to reinstate flights from Inverness to Heathrow after a gap of almost 20 years is unequivocally a "good thing" in my view.
I've taken a look in the British Airways website at the flights available currently (one a day in each direction) and these appear to be at pretty convenient times during the day, to suit both the business and leisure traveller. In particular, those arriving off of long-haul flights into Heathrow early in the morning will probably be able to catch the flight upto Inverness, whereas those who are leaving on a long-haul flight from Heathrow in the late-afternoon or early evening should be able to make the connection on the lunch-time flight out of Inverness in many cases. This will undoubtedly be very convenient for business travellers, but also to long-haul leisure travellers, whether travelling East or West from or to Heathrow.
The convenience for many buisness or leisure travellers of flying through Heathrow however comes at a price, so if one is not going further than London by air, or coming further, there may be little advantage in using this new service from a cost perspective, but for those coming from or going to long-haul destinations using flights via Heathrow, then the convenience of not having to transfer to/from Gatwick will be a major advantage, because it adds to be safe at least a couple of hours when a trip between the two airports is required, not to mention the additional cost, whether you travel via one of the regular scheduled coach services or take a taxi - going around a part of the M25 during working hours is unlikely to be a fast or particularly comfortable experience.
Of course some long-haul flights do go through Gatwick too, so for some travellers it may still be more convenient to take flights to/from Inverness there, but the reinstated link with Heathrow will provide much greater convenience and flexibility for many travellers to/from the Highlands of Scotland.