The two-time A-League winner with Melbourne Victory has spoken at length to The World Game about his departure from the Phoenix on December 5.
The 63-year-old said he hasn't grown tired of coaching or of the A-League.
"Yes, I'd certainly like to coach again," Merrick said. "I love what I do as a coach and I've still got the enthusiasm and the drive for it that I've always had.
"As long as I feel that way I'll always be keen to stay involved, ideally in the A-League.”
When he resigned, after a 2-0 loss to Adelaide United in round nine, Merrick accepted the bulk of the blame for Wellington's poor start to the season - they had lost six of their first nine games.
Talking now, he doesn't back away from that, but stressed that he was hindered by issues like FFA not recognising FIFA windows for international games and a nightmare travel schedule.
Wellington were without a host of star players for their season opener against Melbourne City because they were away on international duty with the New Zealand All Whites.
Those same players then had to rush from the games against Mexico and the USA to Perth for a round two game with only a few days in-between.
The Phoenix lost both of those games, and the next two, as they tried to overcome the interrupted start to their campaign.
"I don't think the FFA are fair to the Phoenix when it comes to the FIFA windows," Merrick said.
"Can you imagine Sydney FC being told six of your players are playing for Australia, so you'll have to play without them? Do you think Sydney or one of the Melbourne teams would put up with that?
"There are two sets of rules here and that's the frustration of the FIFA windows thing.
“If you don’t get off to a good start to the season it becomes a battle to get into the finals and an even tougher battle to win something.
"Adelaide are the only team to overcome a poor start and win in the 11 years of the A-League.”
Wellington lose New Zealand representatives Kosta Barbarouses, Michael McGlinchey, Louis Fenton, Andrew Durante, Tom Doyle, Glen Moss and Matthew Ridenton, and Fiji's Roy Krishna, at various times of the season due to international commitments.
Merrick said the club tried to get its opener against City re-scheduled for later in the season, but FFA wouldn't agree.
He also said the club sought scheduling that made travel easier, by making away games against Adelaide United and Perth back-to-back, for instance, but was again unsuccessful.
"I thought our draw was extremely tough and part of that is related to the fact that we only play 10 of our home games in Wellington, with the other four spread around elsewhere in New Zealand," Merrick said.
"Playing in Perth in round two after a three-day turnaround for those international players coming back from the other side of the world was just the start of it.
"We travel here, there and everywhere - and the more you travel, the less you train.
"I want to win something. I didn't want us to be a team that is just hanging there. I want to develop the team, I want to leave a legacy and bring some youngsters through who are going to be the future of the club.
"We've got a young reserve team, average age 17, playing in the national league in New Zealand and a strong Academy Program.
"But for the whole club and its plan to succeed, the flagship team has to do well, and with the FIFA windows and the travel schedule I could see it being too difficult to win something with the team.
"I felt I was beating my head against the wall all the time, so I thought it was time someone else came in and had a go.
"I thoroughly enjoyed my time at Wellington Phoenix and received enormous support from the sponsors and fans who were very special.
"We recruited well this season and the football staff are very skilled. I feel that I have left the place really healthy with a strong line-up which needs time to gel and I'm sure they'll make the finals."
Not for the first time, the team also had to fly out on Christmas Day for a game in Australia on Boxing Day, this time against Newcastle Jets.
Merrick cited other difficulties, including failure to keep star player Nathan Burns - who moved to FC Tokyo in the J.League after the successful 2014-2015 season - and poor performances by match officials as having a negative impact on results this season.
"In the case of the match officials, the standard has got to improve," he said.
"In the time I was there this season, we had 22 offside calls against us and eight of them were proved to be onside. That's not good when it's my style to have the ball put through for the forwards to chase."
Merrick said the A-League was at risk of being dominated by the richer Sydney and Melbourne clubs who can spend more on marquee and guest players.
"I know Adelaide won it last year, but they can't sustain it because you can't hang on to your good-quality players," he said.
"I think the FFA have made some good decisions and the increased money from the TV rights deal will be great for the clubs, but the FFA have some things to address or the competition will become a two-city thing."