More than 94% of all tickets for the games have been sold, including all those for athletics.
But organisers are at the mercy of competitors. Ennis-Hill was among those who did not go to the 2010 Games in Delhi, amid sanitation and security fears. Other luminaries to opt out included cyclist Sir Chris Hoy whose retirement after the 2012 Olympics is also a blow to 2014. Yet all tickets for the velodrome named after him have sold out.
The loss of Ennis-Hill and defending gold medallist Hoy was just a snapshot of celebrity absenteeism in Delhi. Scotland were minus defending bowls pairs gold medallist Alex Marshall; the respective World and European gymnastic medallists Daniel Keatings and Daniel Purvis; and Andy Murray who opted for the China Open and Shanghai Masters instead of the Games debut of tennis.
The scale of defections prompted debate about the strength of the Commonwealth Games brand and the role of the event on an increasingly commercialised sports calendar. Jamaica lost both Olympic 100 metres champions, Usain Bolt and Shelly-Ann Fraser; Canada missed their reigning World No.1 at 100m hurdles, Priscilla Lopes-Schliep; a raft of Kenyan Olympic medallists opted out; and other England absentees included Olympic cycling champions Victoria Pendleton and Bradley Wiggins; World gymnastics champion Beth Tweddle: defending Commonwealth champions Lisa Dobriskey (1500m) and Philips Idowu (triple jump), World 800 metres bronze medallist Jenny Meadows; and European hurdles bronze medallist Perri Shakes-Drayton.
The Games were generally declared a success, but uncertainty over participation of the biggest names undermines the possibility of maximising media rights fees. Glasgow emphatically needs a glittering show to help re-establish the commercial value of the Games if not its very reputation.
Sheffield woman Ennis, 27, who is an "inspiring ambassador" for 2014, says she is "sorry" not to be competing but, "from a career point of view I am 100% set on returning to full-time athletics once our baby is born, and go for a second gold medal at the Rio Olympics in 2016".
Hormone benefits from pregnancy are well documented. Dundee's Liz McColgan won the World 10,000m title after becoming a mother; Dr Hailey Haining, from Kilbarchan, is 41 and a mother but has the marathon qualifying standard for 2014; while Glasgow's triple Olympian Lee McConnell, a former Commonwealth silver medallist, hopes to return for the Games having given birth to a son in October.