There is a predictable pattern of reactions to new ideas: scepticism; hostility; grudging acceptance; self-congratulation and, finally, sentimentalism.

Paul Finch is programme director of the World Architecture Festival

The London Olympics was a good example; as far as individual buildings are concerned, the long history stretches from Sir Christopher Wren’s design for St Paul’s to Richard Seifert’s Centre Point. Reviled initially, now listed.

The same thing could well happen to the Walkie Talkie, a ‘Marmite’ building currently the object of some extraordinarily miserable criticism. In 30 years’ time, if someone tries to knock it down I predict general outrage and the formation of a protection society.

In the meantime we have to put up with a media frenzy of unwarranted outrage, with moronic comments about there not being acres of grass when you visit the top of the building. You would think the fact that you have to book in advance was a war crime, and that having to produce ID to prove you are the person who made the booking was a breach of human rights legislation.

Even the fact that it is free (unlike the Shard), instead of being celebrated as a welcome new trend for London, gets only grudging acknowledgement. The fact that this is an unprecedented facility is set against the idea that the top of the building is ‘greedy’ because it is broader than the base.

As former City of London Corporation chief planning officer Peter Rees has correctly pointed out, it would be more accurate to say that Rafael Viñoly’s design diminishes as it goes to ground, since the size of the top relates to the site area. At the base, public space has been carved out, whereas the design could have filled the site as just another Mars bar.

Dreary moaning about this marvellous new London attraction is echoed in criticism of Thomas Heatherwick’s Garden Bridge. It is more like a table than a bridge they say. It doesn’t get you anywhere you want to go. But, when built, it will of course be visited by millions of people, as will the Walkie Talkie gardens. The public will vote with their feet and then the critics will suddenly find virtue in what they previously condemned.

Moreover, partly as a result of the Viñoly building (not forgetting that it was the late lamented Francis Golding who pushed for the gardens and got them), the corporation has now adopted a robust attitude to the provision of ‘public rooms’ at the top of office towers: the default position is that they will have to be incorporated. So we can expect to see one at the top of the substitute design for the Helter Skelter, now in production. Ditto in designs for whoever wins the competition to replace what I still think of as the Commercial Union tower.

The new building, by the way, will be the tallest in the City cluster, and why not? Ever since English Heritage decided that the original Miesian block had been altered too much to justify listing, it has been awaiting a top-quality proposal, which Aviva is now facilitating.

For years, only the Post Office Tower allowed the public to enjoy views from the top of a contemporary building. The IRA put a stop to that, and it took three decades before Gerald Ronson was bold enough to adopt the idea, promoted by Cabe, that tall buildings should have public or quasi-public uses at height, hence the bars and restaurants in the Heron Tower (as anyone with any sense still calls it).

In a world of tall buildings, we need to enjoy their height out of working hours, and without necessarily being a tenant. Moaners not required.

Paul Finch is programme director of the World Architecture Festival.