Nigel Farage Has Played His Hand Poorly: High on Rhetoric Low on Tactics.

Nigel demanded a pact with Boris but then chose to make any pact impossible. There can be no upside to this, whatsoever. Soundbites are just soundbites.
Rejecting the whole of Boris's deal could not work when the PM had already gone to the country on the basis of it. Negotiations of that type would have had to have been in place long before the recent parliamentary shenanigans - but they were not.
No deal was already off the table before Boris announced it as the negotiations had already been completed with the EU and the entire election was based on this fact.
No deal would have been better for the UK but not by any great amount. We pretty much have the same structure of the Canada Plus deal that was never going to be too unreasonable.
The appalling damage of the Theresa May surrender had been corrected by Boris, to his eternal credit. The deal is average at best but I will grab average ahead of finding ourselves stuck in the EU. But the principal point is that Nigel had the power to  have negotiated this up to the level of being tolerable - but after the Nigel Brexit Party launch speech, this is now extremely improbable.
Tactically, what Nigel should have done was to have accepted the hard core of the Boris arrangement and then negotiated on all of the many political elements. Within these, there was considerable room for improving the deal as a whole.
Having made this critical - and may I say - extremely dangerous mistake, it is highly improbable that Nigel will now respond to the needs of realpolitik - that would be an unprecedented departure from him. Whether right or wrong, backtracking is not in his nature. I desperately hope that, for once, he will grasp the bigger picture and remove the intolerable threats which not only endanger the process but also the nation's entire future as a sovereign state.

I know a number of people in the ranks of the Brexit Party who are horrified that Nigel appears to be putting the needs of the nation behind keeping the BP at centre stage.

Threatening someone with whom you wish to build an alliance is absurd. It is now extremely doubtful that Boris can even use back channels for trying to create some sort of vague compact.
The threat to challenge all Tories in all Tory seats is simply insane. Splitting the vote that way can only result in Boris failing to secure a majority. Those journos who have called Nigel 'the greatest threat to leaving the EU' are probably not wrong - especially as one poll has already got Boris down to a mere 8% lead over Labour!
What must never be forgotten is that there is now a huge number of voters who are totally fed up with the very word 'Brexit' and will do anything to get back to some form of normality. These people adore the fact that the Boris deal would bring an end to three and a half years of leftist-caused chaos. But they do not care who caused it - they just want the whole thing to go away. The one upside to that is that Labour's second referendum can only keep things going - something that so many voters do not want.
Should that happen - it is almost inevitable that we shall be in the EU to stay!
I could cry. Perhaps the only hope is that the poll which showed the BP on 7% was exaggerating their current support.
If the BP causes us to have to remain in the EU (which effectively was what the May deal was all about) they will die.
Few Brexiteers will be able to forgive them.